Control apparatus, image pickup apparatus, image pickup system, lens apparatus, control method, and non-transitory computer-readable storage medium

ABSTRACT

A control apparatus includes a focus detector configured to perform focus detection based on an image signal obtained via a first optical system, the first optical system having a shallowest depth of field in a plurality of optical systems having focal lengths different from each other, and a controller configured to perform focus control of the plurality of optical systems based on an output signal from the focus detector.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a compound-eye image pickup apparatusconfigured by arraying a plurality of optical systems.

2. Description of the Related Art

Previously, with respect to a compound-eye image pickup apparatusincluding a plurality of optical systems disposed parallel to eachother, an image pickup apparatus which performs focus control (AFcontrol) is known. In the compound-eye image pickup apparatus, a load inperforming the AF control increases when a defocus amount for each ofthe optical systems needs to be calculated.

Japanese Patent Laid-open No. 2004-207774 discloses a compound-eye imagepickup apparatus which performs AF control by a contrast detectionmethod by using a short focus optical system based on an image signalobtained from an image pickup element corresponding to the short focusoptical system having a deep depth of focus, and then it performs AFcontrol of a long focus optical system based on an AF result of theshort focus optical system. Japanese Translation of PCT InternationalApplication Publication No. 2010-521005 discloses a compound-eye imagepickup apparatus which performs AF control of an optical system selectedfor capturing an image by using an output signal from an image pickupelement via the other optical system when one optical system is selectedfor capturing the image of two optical systems. As described above, inthe compound-eye image pickup apparatus disclosed in Japanese PatentLaid-open No. 2004-207774 and Japanese Translation of PCT InternationalApplication Publication No. 2010-521005, the AF control is performed byusing the image signal obtained from one optical system, and thus a loadin performing the AF control is reduced.

However, the compound-eye image pickup apparatus disclosed in JapanesePatent Laid-open No. 2004-207774 performs the AF by the contrastdetection method by using the short focus optical system having a deepdepth of field. Therefore, when the AF result obtained by using theshort focus optical system is applied to the long focus optical systemhaving a shallow depth of focus, the accuracy of the focus control isdeteriorated. The compound-eye image pickup apparatus disclosed inJapanese Translation of PCT International Application Publication No.2010-521005 performs the AF control by using the short focus opticalsystem having a deep depth of field, and therefore the accuracy of theAF control in other optical systems having different depth of field isdeteriorated. Accordingly, in the configurations of Japanese PatentLaid-open No. 2004-207774 and Japanese Translation of PCT InternationalApplication Publication No. 2010-521005, focal points in a plurality ofoptical systems cannot be determined efficiently and accurately.

SUMMARY OF THE INVENTION

The present invention provides a control apparatus, an image pickupapparatus, an image pickup system, a lens apparatus, a control method,and a non-transitory computer-readable storage medium which are capableof efficiently and accurately determining (detecting) focal points of aplurality of optical systems having focal lengths different from eachother.

A control apparatus as one aspect of the present invention includes afocus detector configured to perform focus detection based on an imagesignal obtained via a first optical system, the first optical systemhaving a shallowest depth of field in a plurality of optical systemshaving focal lengths different from each other, and a controllerconfigured to perform focus control of the plurality of optical systemsbased on an output signal from the focus detector.

An image pickup apparatus as another aspect of the present inventionincludes an image pickup element configured to photoelectrically convertan optical image formed via a plurality of optical systems having focallengths different from each other, a focus detector configured toperform focus detection based on an image signal obtained via a firstoptical system, the first optical system having a shallowest depth offield in the plurality of optical systems, and a controller configuredto perform focus control of the plurality of optical systems based on anoutput signal from the focus detector.

An image pickup system as another aspect of the present inventionincludes a plurality of optical systems having focal lengths differentfrom each other, an image pickup element configured to photoelectricallyconvert an optical image formed via the plurality of optical systems, afocus detector configured to perform focus detection based on an imagesignal obtained via a first optical system, the first optical systemhaving a shallowest depth of field in the plurality of optical systems,and a controller configured to perform focus control of the plurality ofoptical systems based on an output signal from the focus detector.

A lens apparatus as another aspect of the present invention includes aplurality of optical systems having focal lengths different from eachother, and a controller configured to perform focus control of theplurality of optical systems based on an image signal obtained via afirst optical system, the first optical system having a shallowest depthof field in the plurality of optical systems.

A control method as another aspect of the present invention includes thesteps of performing focus detection based on an image signal obtainedvia a first optical system, the first optical system having a shallowestdepth of field in a plurality of optical systems having focal lengthsdifferent from each other, and performing focus control of the pluralityof optical systems based on a result of the focus detection.

A non-transitory computer-readable storage medium as another aspect ofthe present invention stores a program which causes a computer toexecute a process including performing focus detection based on an imagesignal obtained via a first optical system, the first optical systemhaving a shallowest depth of field in a plurality of optical systemshaving focal lengths different from each other, and performing focuscontrol of the plurality of optical systems based on a result of thefocus detection.

Further features and aspects of the present invention will becomeapparent from the following description of exemplary embodiments withreference to the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of a compound-eye image pickup apparatus inEmbodiment 1.

FIG. 2 is a perspective view of an image pickup unit in each ofEmbodiments 1 to 3.

FIG. 3 is a front view of the image pickup unit in each of Embodiments 1to 3.

FIG. 4 is an explanatory diagram of captured images in each ofEmbodiments 1 to 3.

FIG. 5 is a flowchart of illustrating an image capturing operation ofthe compound-eye image pickup apparatus in Embodiment 1.

FIG. 6 is a block diagram of a compound-eye image pickup apparatus inEmbodiment 2.

FIG. 7 is a flowchart of illustrating an image capturing operation ofthe compound-eye image pickup apparatus in Embodiment 2.

FIG. 8 is a block diagram of a compound-eye image pickup apparatus inEmbodiment 3.

FIG. 9 is a flowchart of illustrating an image capturing operation ofthe compound-eye image pickup apparatus in Embodiment 3.

FIG. 10 is a block diagram of a compound-eye image pickup apparatus inEmbodiment 4.

FIG. 11 is an explanatory diagram of a focus drive mechanism of thecompound-eye image pickup apparatus in Embodiment 4.

FIG. 12 is a flowchart of illustrating an image capturing operation ofthe compound-eye image pickup apparatus in Embodiment 4.

FIGS. 13A to 13D are cross-sectional views of lenses of a wide facet, awide-middle facet, a tele-middle facet, and a tele facet of acompound-eye optical system in Embodiment 4.

FIGS. 14A to 14D are aberration diagrams of Numerical example 1corresponding to the compound-eye optical system in Embodiment 4.

FIGS. 15A to 15D are cross-sectional views of lenses of a wide facet, awide-middle facet, a tele-middle facet, and a tele facet of acompound-eye optical system in Embodiment 4.

FIGS. 16A to 16D are aberration diagrams of Numerical example 2corresponding to the compound-eye optical system in Embodiment 4.

FIGS. 17A to 17D are cross-sectional views of lenses of a wide facet, awide-middle facet, a tele-middle facet, and a tele facet of acompound-eye optical system in Embodiment 4.

FIGS. 18A to 18D are aberration diagrams of Numerical example 3corresponding to the compound-eye optical system in Embodiment 4.

FIGS. 19A and 19B are cross-sectional views of lenses of a wide facetand a tele facet of a compound-eye optical system in Embodiment 4.

FIGS. 20A and 20B are aberration diagrams of Numerical example 4corresponding to the compound-eye optical system in Embodiment 4.

FIG. 21 is an explanatory diagram of a principle of AF control by acontrast detection method in each of Embodiments 1, 3, and 4.

FIG. 22 is an explanatory diagram of a depth of field in the AF controlby the contrast detection method in each of Embodiments 1, 3, and 4.

FIG. 23 is an explanatory diagram of a principle of AF control by aphase-difference detection method in each of Embodiments 2 to 4.

FIG. 24 is an explanatory diagram of a correlation calculation of the AFcontrol by the phase-difference detection method in each of Embodiments2 to 4.

FIG. 25 is an explanatory diagram of a movement of an image plane due tovariation of an object distance in Embodiment 4.

FIG. 26 is an explanatory diagram of a correction of the image plane bya movement of a focus unit in Embodiment 4.

DESCRIPTION OF THE EMBODIMENTS

Exemplary embodiments of the present invention will be described belowwith reference to the accompanied drawings.

An image pickup apparatus in this embodiment is a compound-eye imagepickup apparatus which controls a plurality of imaging optical systems(a plurality of optical systems) and a plurality of image pickupelements (or a plurality of image pickup regions) to capture a pluralityof images at the same time. In this embodiment, as the imaging opticalsystems, a plurality of fixed-focal optical systems having differentfocal lengths from each other are disposed, and the image pickupelements having the image pickup regions corresponding to the respectiveoptical systems are provided, and thus zooming is achieved. The numberof the image pickup elements may be plural, or alternatively a singleimage pickup element may be divided into a plurality of image pickupregions.

A digital zoom unit is known which performs trimming of a part of animage captured by an image pickup apparatus and magnifies a range wherethe trimming of the captured image is performed up to a predeterminedsize so as to acquire an effect similar to that of artificial zooming.Furthermore, a zoom lens is known which combines digital zooming andoptical zooming to achieve a higher variable power ratio.

Applying such a method, the effect similar to that of the artificialzooming can be obtained by providing the imaging optical systems havingdifferent angles of field in the compound-eye image pickup apparatus andinterpolating an angle of field between the different angles of field byusing a digital zoom technology. As a simple method, an image with amiddle-angle of field, which has a high resolution in part but has a lowresolution in other parts, can be obtained by fitting, into a part of animage obtained by performing digital zooming, a telephoto image obtainedby an image pickup element corresponding to a telephoto lens. In otherwords, in order to achieve a continuous zooming function in thecompound-eye image pickup apparatus, it is important to include aconfiguration in which a plurality of in-focus images with differentangles of field can be captured simultaneously. If at least one of theimages is an out-of-focus image which is not in focus, the effect of themethod described above is decreased or lost, and accordingly thecontinuous zooming function with a high resolution cannot be achieved.Thus, the AF function is important in the compound-eye image pickupapparatus. However, a load of the image pickup apparatus increases if AFcontrol and processing is to be individually performed.

Referring to FIG. 21, an example of a drive operation of a focus lensduring the AF by a contrast detection method will be described. FIG. 21is an explanatory diagram of a principle of the AF control by thecontrast detection method. In FIG. 21, a dashed line indicates arelationship between an AF evaluation value and a position of a focuslens in an optical system having a deep depth of field, and a solid lineindicates a relationship between an AF evaluation value and a positionof a focus lens in an optical system having a shallow depth of field.The AF evaluation value is a value obtained by extracting a highfrequency component by applying a filter to an image signal in an imageregion where focusing is to be performed. As illustrated in FIG. 21, theAF evaluation value is a value representing a sharpness (level ofcontrast) of an image, and it can be used as a value of representing afocus state of an image pickup optical system since the sharpness of thein-focus image is higher and the sharpness of the blurred image islower.

In FIG. 21, when the focus lens is driven from a start position of aclimbing drive in a rightward direction in the drawing, as indicated byan arrow A, it is detected that the AF evaluation value has passed thepeak and is decreasing. In this case, it is assumed that a focal pointhas passed, and the climbing drive operation is finished and the focuslens goes back to a position where the AF evaluation value is maximized,and then a fine drive operation starts. By the fine drive operation, thefocal point is detected in more detail to determine a final position ofthe focus lens. On the other hand, when the focus lens is driven fromthe start position of the climbing drive in a leftward direction in thedrawing, as indicated by an arrow B, it is detected that the AFevaluation value is decreasing without passing the peak. In this case,it is determined that a moving direction of the focus lens is erroneous,and the climbing drive operation in a reverse direction continues.During the climbing drive operation, a moving amount of the focus lensper a certain period of time, i.e., a moving velocity, is typicallylarger than that during the fine drive operation. In addition, when theAF evaluation value is determined actually, it is typically determinedthat it reaches the focal point if it is within a certain thresholdrange. This is because an output similar to that in an in-focus state isobtained as a captured image within a depth of focus in the image pickupoptical system. The depth of focus in the optical system is representedby 2×Fno×6 where Fno is an F number and 6 is a diameter of a permissiblecircle of confusion with respect to a pixel pitch of an image pickupelement.

Referring to FIG. 22, an in-focus threshold value of the AF evaluationvalue will be described considering depths of focus in a graph for theoptical system having the deep depth of field indicated by the dashedline and a graph for the optical system having the shallow depth offield indicated by the solid line depicted in FIG. 21. FIG. 22 is anexplanatory diagram of the depth of field during the AF control by thecontrast detection method. In FIG. 22, dashed-dotted lines indicatein-focus threshold values of the AF evaluation value.

In the drawing, the threshold value ranges for the optical systems areillustrated to be identical since it is assumed that the F numbers Fnoof the optical systems are identical. In this case, a range in which itis determined that the focus lens in each optical system is in thein-focus state is indicated by an arrow in the drawing. As can be seenin FIG. 22, the position of the focus lens can be accurately determinedwith an increase of the sharpness in the graph as the optical systemhaving the shallow depth of field. Since the optical system having theshallow depth of field tends to have high sensitivity of an image-planemoving amount with respect to the position of the focus lens, theposition of the focus lens can be determined with high accuracy comparedto the optical system having the deep depth of field.

For example, a compound-eye image pickup apparatus in this embodimentincludes an acquirer which acquires an image capturing condition forcapturing an image by using a plurality of imaging optical systems, anda determiner which determines a first imaging optical system having theshallowest depth of field to be used for capturing the image. In thisconfiguration, optical systems used for the AF control or the AF processcan be controlled to select an optical system in which a position of afocus lens can be determined with high accuracy. As a result, reductionof a load of the control and the process during the AF as a whole of theimage pickup apparatus and improvement of a focusing accuracy can beachieved.

Embodiment 1

First of all, referring to FIGS. 1 to 3, a compound-eye image pickupapparatus in Embodiment 1 of the present invention will be described.FIG. 1 is a block diagram of a compound-eye image pickup apparatus 1 inthis embodiment. FIG. 2 is a perspective view of an image pickup unit100 in the compound-eyen image pickup apparatus 1. FIG. 3 is a frontview of the image pickup unit 100.

The compound-eye image pickup apparatus 1 includes the image pickup unit100, an A/D converter 10, an image processor 20, an AF gate 30, an AFsignal processor 31 (focus detector), a system controller 90, and animage pickup controller 50 (controller). Furthermore, the compound-eyeimage pickup apparatus 1 includes an imaging optical system determiner51 (determiner), a focus unit movement position calculator 52(calculator), an information input unit 60, an information acquirer 61(acquirer), an image recording medium 70, a memory 71, and a displayunit 80. The compound-eye image pickup apparatus 1 is a lens-integratedimage pickup apparatus, but it is not limited thereto. For example, thecompound-eye image pickup apparatus 1 may be an image pickup systemwhich includes an image pickup apparatus body including an image pickupelement and a lens apparatus including an imaging optical system (imagepickup optical system) removably attached to the image pickup apparatusbody.

As illustrated in FIGS. 1 to 3, the image pickup unit 100 includes eightimaging optical systems (image pickup optical systems) 110 a, 120 a, 130a, 140 a, 110 b, 120 b, 130 b, and 140 b, each of which forms an opticalimage of an object. The image pickup unit 100 includes a plurality ofimage pickup elements 210 a to 210 h which correspond to the respectiveimaging optical systems 110 a to 140 b. FIG. 1 illustrates a crosssection of the image pickup unit 100 including optical axes OA1 and OA2of the imaging optical systems 110 a and 140 a in the image pickup unit100, respectively.

Each imaging optical system includes a focus unit F (focus lens unit orfront unit) and a rear unit R (fixed lens unit). FIG. 1 illustratesfocus units 110 aF and 140 aF and rear units 110 aR and 140 aRcorresponding to the imaging optical systems 110 a and 140 a,respectively. The focus unit F is driven so as to move while an objectposition changes (i.e., while focusing is performed). The rear unit R isfixed during the focusing, and other members such as a stop (notillustrated) are included in each imaging optical system. Thus, thecompound-eye image pickup apparatus 1 of this embodiment uses a partialfocusing method in which a part of the optical systems is moved duringthe focusing. The number of focus lenses mounted on the focus unit Fincluded in each imaging optical system is one or more.

The plurality of image pickup elements 210 a to 210 f are heldintegrally and they constitute an image pickup element unit 200. Theimage pickup elements 210 a and 210 b correspond to the imaging opticalsystems 110 a and 120 a, respectively, and the image pickup elements 210c and 210 d correspond to the imaging optical systems 110 b and 120 b,respectively. The image pickup elements 210 e and 210 f correspond tothe imaging optical systems 140 a and 130 a, respectively, and the imagepickup elements 210 g and 210 h correspond to the imaging opticalsystems 140 b and 130 b, respectively.

As illustrated in FIG. 3, optical axes of the eight imaging opticalsystems 110 a, 120 a, 130 a, 140 a, 110 b, 120 b, 130 b, and 140 b areapproximately parallel to each other. The two imaging optical systems(for example, imaging optical systems 110 a and 110 b) to which anidentical reference numeral is added have an identical focal length. Inthis embodiment, four pairs of imaging optical systems 110, 120, 130,and 140 having focal length different from each other are provided. Theimaging optical systems 110 a and 110 b are a pair of wide-angle imagingoptical systems having the shortest focal length among the eight imagingoptical systems. The imaging optical systems 120 a and 120 b have afocal length longer than that of the imaging optical systems 110 a and110 b. The imaging optical systems 130 a and 130 b have a focal lengthlonger than that of the imaging optical systems 120 a and 120 b. Theimaging optical systems 140 a and 140 b have a focal length longer thanthat of the imaging optical systems 130 a and 130 b.

FIG. 4 is an explanatory diagram of shot images (captured images) inthis embodiment, and illustrates captured images 1110 a, 1120 a, 1130 a,and 1140 a corresponding to the imaging optical systems 110 a, 120 a,130 a, and 140 a, respectively. As illustrated in FIG. 4, the capturedimage 1110 a corresponding to the imaging optical system 110 a has thewidest object space. The captured images 1120 a, 1130 a, and 1140 acorresponding to the imaging optical systems 120 a, 130 a, and 140 ahave narrower captured object spaces depending on focal lengths.

In FIG. 1, the imaging optical systems 110 a and 140 a constitute acompound eye. The image pickup elements 210 a and 210 e convert, toelectric signals (analog signals), optical images formed on surfaces(image pickup surfaces) of the image pickup elements 210 a and 210 e viathe imaging optical systems 110 a and 140 a, respectively. The A/Dconverter 10 coverts the analog signals output from the image pickupelements 210 a to 210 f to digital signals, and then it supplies thedigital signals to image processor 20 or the AF gate 30. The imageprocessor 20 performs predetermined pixel interpolation processing,color conversion processing, or the like on each of image data from theA/D converter 10, and it also performs a predetermined calculation(arithmetic processing) by using each of the captured image data. Aresult processed by the image processor 20 is sent to the systemcontroller 90.

The image processor 20 may include a super-resolution processor(super-resolution processing unit), image synthesizer (image synthesisunit), a blur adder, an object remover, or the like. Thesuper-resolution processor performs super-resolution processing on animage by using a plurality of images. The image synthesizer uses aplurality of images to generate a single synthesized image having imagecharacteristics different from those of the plurality of images, and forexample it performs processing to reduce a noise level or create ahigh-dynamic-range image. The image characteristics include, for exampleat least one of a dynamic range, a resolution, a blurring amount, anangle of field, and a rate of removal of a captured object in an image.The blur adder adds (applies) a blur to an image based on distanceinformation. The object remover obtains for example an image in which abackground, which is specified as an unnecessary object by a user, otherthan a main object is removed.

The AF gate 30 supplies, to the AF signal processor 31, only a signal ina region (focus detection region or AF frame), which is to be used forfocus detection, set by the system controller 90 among output signals ofall pixels from the A/D converter 10. The AF signal processor 31 appliesa filter to a pixel signal (focal signal or image signal) supplied fromthe AF gate 30 to extract a high frequency component, and it generatesan AF evaluation value. The AF evaluation value is output to the systemcontroller 90. The information input unit 60 detects information (data)relating to a desired image capturing condition which is selected andinput by the user, and it supplies the data to the system controller 90.The information input unit 60 includes the information acquirer 61. Theinformation acquirer 61 acquires current image capturing conditioninformation (such as an aperture value (F number), a focal length, anexposure time, and an image pickup optical system to be used) from theimage pickup controller 50 or the system controller 90.

The imaging optical system determiner 51 determines (selects) an imagingoptical system to acquire a pixel output signal to be supplied to the AFgate 30 based on the image capturing condition information obtained fromthe information acquirer 61. The focus unit movement position calculator52 calculates a focus unit movement position of the other imagingoptical systems that are not selected, based on a focus unit position ofthe imaging optical system selected by imaging optical system determiner51 and a lookup table or a function stored in the memory 71. The systemcontroller 90 controls the image pickup controller 50 based on thesupplied data. The image pickup controller 50 moves the focus unit F andcontrols each image pickup element according to the aperture value ofeach imaging optical system and the exposure time to acquire a necessaryimage.

The image recording medium 70 stores a file header of an image file, inaddition to a plurality of still images or moving images. The memory 71stores the lookup table relating to a relative position of the focusunit of each imaging optical system or the function of calculating therelative position of the focus unit. The display unit 80 displays animage, a status, an error, and the like, and it includes for example aliquid crystal display element.

Next, referring to FIG. 5, an AF control method performed by thecompound-eye image pickup apparatus 1 will be described. FIG. 5 is aflowchart of illustrating an image capturing operation (AF controlmethod) of the compound-eye image pickup apparatus 1. Each step in FIG.5 is performed by an instruction of the system controller 90 in thecompound-eye image pickup apparatus 1. In other words, the AF controlmethod illustrated in FIG. 5 can be realized as a program which causesthe system controller including a microcomputer (processor) to execute afunction of each step.

First, when the user inputs an image capturing signal (for example, whenthe user presses a release button), the system controller 90 starts AFcontrol. When the AF control starts, first at step S100, the systemcontroller acquires the image capturing condition. The image capturingcondition is for example focal lengths of imaging optical systems to beused for capturing an image, Fno data (aperture value data), diameters 6of permissible circles of confusion relating to pixel sizes of the imagepickup elements, which are image capturing condition informationobtained from the information acquirer 61.

Subsequently, at step S101, the system controller 90 selects an imagingoptical system having the shallowest depth of field in the imagingoptical systems to be used for capturing the image, based on the focallengths, the Fno data, and the diameters of the permissible circles ofconfusion acquired at step S100.

Hereinafter, a method of selecting the imaging optical system in thecompound-eye image pickup apparatus 1 will be described. Depths of field(rear-side depth of field d1 and front-side depth of field d2)indicating ranges in which an actual object is determined to be in focusare represented by the following expressions (1) and (2), respectively.

$\begin{matrix}{{d\; 1} = \frac{\delta \times {Fno} \times L^{2}}{f^{2} - {\delta \times {Fno} \times L}}} & (1) \\{{d\; 2} = \frac{\delta \times {Fno} \times L^{2}}{f^{2} + {\delta \times {Fno} \times L}}} & (2)\end{matrix}$

In expressions (1) and (2), symbol f denotes a focal length of theimaging optical system, symbol 6 denotes a diameter of a permissiblecircle of confusion, symbol Fno denotes an F number of the imagingoptical system, and symbol L denotes an object distance. As can be seenfrom expressions (1) and (2), the depth of field decreases, with respectto an identical object distance, with increasing the focal length of theimaging optical system, with decreasing Fno, or with decreasing thediameter of the permissible circle of confusion. In this embodiment, theimaging optical system determiner 51 selects a first imaging opticalsystem which satisfies the following conditional expression (3)introduced from expressions (1) and (2).

$\begin{matrix}{\frac{f_{i}^{2}}{\delta_{i}{Fno}_{i}} \leq \frac{f_{1}^{2}}{\delta_{1}{Fno}_{1}}} & (3)\end{matrix}$

In conditional expression (3), symbols f_(i), Fno_(i), and δ_(i) denotea focal length, an F number, and a diameter of permissible circle ofconfusion with respect to an optical system (i-th optical system) in theeight imaging optical systems, respectively. Symbols f_(1r) Fno₁, and δ₁denote a focal length, an F number, and a diameter of permissible circleof confusion with respect to the selected first imaging optical system,respectively. When pixel sizes of the image pickup elementscorresponding the respective imaging optical systems are identical, thediameters of the permissible circles of confusion are identical.Accordingly, conditional expression (3) can be replaced with thefollowing conditional expression (3a).

$\begin{matrix}{\frac{f_{i}^{2}}{{Fno}_{i}} \leq \frac{f_{1}^{2}}{{Fno}_{1}}} & ( {3a} )\end{matrix}$

In this embodiment, it is assumed that the pixel sizes of the respectiveimage pickup elements are identical and also the F numbers Fno of therespective imaging optical systems are identical. Accordingly, theimaging optical system determiner 51 selects the first imaging opticalsystem satisfying conditional expression (3a). In this embodiment, theimaging optical system determiner 51 selects, as the first imagingoptical system, the imaging optical system 140 a having the longestfocal length.

Subsequently, at step S102, the system controller 90 finely drives thefocus unit 140 aF via the image pickup controller 50. For more details,the system controller 90 determines, as a focus detection region, animage center region or a region specified by a user via the informationinput unit 60, and it sets the AF gate 30 so that only an image signalin the determined focus detection region is supplied to the AF signalprocessor 31. Then, the system controller 90 acquires an AF evaluationvalue that is generated by the AF signal processor 31 based on the imagesignal in the focus detection region. Furthermore, the system controller90 moves the focus unit 140 aF from side to side (from right to left andfrom left to right) by a fine amount, and again it acquires the AFevaluation values (i.e., an AF evaluation value obtained by moving tothe left and an AF evaluation value obtained by moving to the right).

Subsequently, at step S103, the system controller 90 performs anin-focus determination based on the AF evaluation value obtained by thefine drive performed at step S102. When the system controller 90determines that the imaging optical system is in an in-focus state, theflow proceeds to step S108. On the other hand, when the systemcontroller 90 determines that the imaging optical system is not in thein-focus state (i.e., the imaging optical system is in an out-of-focusstate), the flow proceeds to step S104. For more details, the systemcontroller 90 compares the AF evaluation value at a current position(stop position) of the focus unit 140 aF acquired at step S102 with thetwo AF evaluation values acquired after moving from side to side by thefine amount. When both of the two AF evaluation values acquired aftermoving from side to side by the fine amount are lower than the currentAF evaluation value, the system controller 90 determines that thecurrent position (stop position) of the focus unit 140 aF is located ata peak position of the AF evaluation value. In other words, the systemcontroller 90 determines that the imaging optical system is in thein-focus state and the flow proceeds to step S108. On the other hand,when any one of the two AF evaluation values acquired after moving fromside to side by the fine amount is higher than the current AF evaluationvalue, the system controller 90 determines that the imaging opticalsystem is in the out-of-focus state and the flow proceeds to step S104.

For the determination result of the out-of-focus state, at step S104,the system controller 90 determines whether a focusing direction (i.e.,direction of the peak position of the AF evaluation value) can bedetermined. When the system controller 90 can determine the focusingdirection, the flow proceeds to step S105. On the other hand, when thesystem controller 90 cannot determine the focusing direction, the flowreturns to step S102. For more details, when the AF evaluation valueacquired after moving to the left by a fine amount is lower than thecurrent AF evaluation value and the AF evaluation value acquired aftermoving to the right by a fine amount is higher than the current AFevaluation value, the system controller 90 determines that a focal pointexists at the right side (i.e., focusing direction is the rightwarddirection) and the flow proceeds to step S105. When the AF evaluationvalue acquired after moving to the left by the fine amount is higherthan the current AF evaluation value and the AF evaluation valueacquired after moving to the right by the fine amount is lower than thecurrent AF evaluation value, the system controller 90 determines thatthe focal point exists at the left side (i.e., focusing direction is theleftward direction) and the flow proceeds to step S105. On the otherhand, when any one of the AF evaluation values cannot be acquiredappropriately, the system controller 90 determines that the focusingdirection cannot be determined, and the flow returns to step S102.

At step S105, the system controller 90 performs climbing drive of thefocus unit 140 aF by a drive amount larger than that of the fine drivein a direction determined at step S104. The detail of the climbing driveis the same as the description with reference to FIG. 21, and thereforethe description is omitted. Subsequently, at step S106, the systemcontroller 90 determines whether the peak (peak position) of the AFevaluation value can be detected. When the peak of the AF evaluationvalue is detected, the flow proceeds to step S107. On the other hand,the peak of the AF evaluation value is not detected, the flow returns tostep S105. For more details, referring to FIG. 21, when the focus lensis driven from a start position of the climbing drive in the rightwarddirection in the drawing, as indicated by an arrow A, it is detectedthat the AF evaluation value has passed the peak and is decreasing. Inthis case, the system controller 90 determines that the peak of the AFevaluation value can be detected, and the flow proceeds to step S107. Onthe other hand, when it is not detected that the AF evaluation value haspassed the peak and is decreasing, the system controller 90 determinesthat the AF evaluation value does not reach the peak yet, and the flowreturns to step S105 to continue the climbing drive.

At step S107, the system controller 90 moves the focus unit 140 aF tothe peak position detected at step S106. After the system controller 90moves the focus unit 140 aF to the peak position, the flow returns tostep S102 to continue the process.

When it is determined at the imaging optical system is in the in-focusstate at step S103, at step S108, the system controller 90 stops,through the image pickup controller 50, the drive of the focus unit 140aF at the position where it is determined that the imaging opticalsystem is in the in-focus state at step S103. Then, at step S109, thesystem controller 90 detects and acquires position information of thestopped focus unit 140 aF.

Subsequently, at step S110, the system controller 90 calculates movementpositions of focus units included in the imaging optical systems otherthan the selected imaging optical system 140 a. The imaging opticalsystems in this embodiment have the focal lengths different from eachother, and configurations of the imaging optical systems are differentfrom each other. Accordingly, positions of the focus units to focus animage on the surfaces of the image pickup elements for an arbitraryobject distance are also different from each other. However, a positionof the focus unit for a certain object distance is uniquely determinedin each of the imaging optical systems. In other words, with respect toeach of the imaging optical systems, the position of the focus unit tofocus the image on the surface of the image pickup element for a certainobject distance always maintains a relative relation. Therefore, if theposition of the focus unit included in an imaging optical system for acertain object distance is determined, the positions the focus unitsincluded in the other imaging optical systems can be determined based onthe relative relations. In this embodiment, for example, the relativeposition relations described above are stored as a lookup table in thememory 71. The positions of the focus units included in the otherimaging optical systems corresponding to the stop position of the focusunit 140 aF can be determined based on the lookup table and the stopposition information of the focus unit 140 aF determined at thepreceding stage. As another method, the relative relation describedabove is stored as a function in the memory 71, and the positions of thefocus units included in the other imaging optical systems correspondingto the stop position can be determined based on the function and thestop position information of the focus unit 140 aF determined at thepreceding stage.

Subsequently, at step S111, the system controller 90 moves the focusunits F to the respective movement positions, calculated at step S110,of the focus units included in the imaging optical systems other thanthe imaging optical system 140 a and then it stops the focus units F.Thus, the AF control of this embodiment is completed.

According to this embodiment, as an optical system to be used for AFcontrol, an optical system capable of determining a position of a focuslens with high accuracy can be selected. As a result, a reduction of aprocessing load and improvement of a focusing accuracy during the AFcontrol can be achieved.

Embodiment 2

Next, referring to FIG. 6, a compound-eye image pickup apparatus inEmbodiment 2 of the present invention will be described. FIG. 6 is ablock diagram of a compound-eye image pickup apparatus 2 in thisembodiment. The compound-eye image pickup apparatus 2 of this embodimentis different from the compound-eye image pickup apparatus 1 ofEmbodiment 1 in that the compound-eye image pickup apparatus 2 includesa phase-difference AF gate 32 and a phase-difference AF signal processor33, instead of the AF gate 30 and the AF signal processor 31.

The phase-difference AF gate 32 supplies, to the phase-difference AFsignal processor 33 (focus detector), only a signal in a focus detectionregion or an AF frame set by the system controller 90 among outputsignals of all pixels from the A/D converter 10. The phase-difference AFsignal processor 33 performs processing of a phase-difference detectionmethod on a pixel signal (focal signal or image signal) supplied fromthe phase-difference AF gate 32 to calculate a defocus amount. Thedefocus amount is output to the system controller 90.

The information input unit 60 detects information (data) relating to adesired image capturing condition which is selected and input by a user,and it supplies the data to the system controller 90. The informationinput unit 60 includes the information acquirer 61. The informationacquirer 61 acquires current image capturing condition information (suchas an aperture value (F number), a focal length, an exposure time, andan image pickup optical system to be used) from the image pickupcontroller 50 or the system controller 90. The imaging optical systemdeterminer 51 determines (selects) an imaging optical system to acquirea pixel output signal to be supplied to the phase-difference AF gate 32based on the image capturing condition information obtained from theinformation acquirer 61. The focus unit movement position calculator 52calculates a position of a focus unit included in the imaging opticalsystem selected by the imaging optical system determiner 51 based on thedefocus amount. Furthermore, the focus unit movement position calculator52 calculates movement positions of focus units included in the otherimaging optical systems which are not selected, based on the position ofthe focus unit included in the selected imaging optical system and alookup table or a function stored in the memory 71. The systemcontroller 90 controls the image pickup controller 50 based on thesupplied data. The image pickup controller 50 moves the focus unit F andcontrols each image pickup element according to the aperture value ofeach imaging optical system and the exposure time to acquire a necessaryimage. The other configurations of the compound-eye image pickupapparatus 2 are the same as those of the compound-eye image pickupapparatus 1 described with reference to FIG. 1, and thereforedescriptions thereof are omitted.

Hereinafter, a principle of a phase-difference AF will be describedbriefly. Typically, as described in the background of the invention,light beams, emitted from an object, passing through exit pupil regionsdifferent from each other in an image pickup optical system are imagedon a pair of line sensors, and a shift amount of relative positions of apair of image signals obtained by photoelectrically converting an objectimage is obtained. In the compound-eye image pickup apparatus of thisembodiment, only an image signal from the focus detection region isextracted from image signals obtained by two imaging optical systemshaving the same focal length, and thus the similar effect can beobtained. Hereinafter, as one example, a principle of thephase-difference AF in which one-line image signals is used similarly toa typical line sensor will be described. Outputs of image signals (twoimages) from the focus detection region among image signals obtained bythe two imaging optical systems are as illustrated in FIG. 23.

FIG. 23 is an explanatory diagram of a principle of the AF control bythe phase-difference detection method, and with respect to outputs ofimage signals (two images) from the focus detection region, intervals(gaps) between the two images (image interval) are different dependingon an in-focus state, a front-focus state, and a rear-focus state. Thefocusing is performed by moving a lens so that the image intervalbecomes an interval obtained in the in-focus state. A moving amount ofthe lens, i.e., a defocus amount as a moving amount of an image plane,is calculated based on the interval of the two images. The calculationis performed by the following algorithm.

First, outputs from the two image pickup elements are input as data.Then, a correlation calculation is performed by using the two outputs.As a correlation calculation method, there is a method which is calledMIN algorithm. A correlation amount U0 is represented by the followingexpression (4), where A[1]-A[n] are one of the output data and B[1]-B[n]are the other of the output data.

$\begin{matrix}{{U\; 0} = {\sum\limits_{j}^{m}\; {\min ( {{A\lbrack j\rbrack},{B\lbrack j\rbrack}} )}}} & (4)\end{matrix}$

In expression (4), symbol min (a,b) denotes a function indicating asmaller value of values a and b.

Subsequently, as illustrated in FIG. 24, a correlation amount U1 betweendata in which an image A is shifted by 1 bit in an arrow direction inthe drawing and data of an image B is calculated. The correlation amountU1 is calculated by the following expression (5).

$\begin{matrix}{{U\; 1} = {\sum\limits_{j}^{m}\; {\min \; ( {{A\lbrack {j + 1} \rbrack},{B\lbrack j\rbrack}} )}}} & (5)\end{matrix}$

Similarly, correlation amounts obtained by shifting by 1 bit arecalculated in sequence. When the two images coincide with each other,the correlation amount is maximized. Accordingly, a shift amountcorresponding to the maximum value is obtained, and based on itsprevious and next data, a true maximum value Umax of the correlationamount is obtained by interpolation, and thus the shift amount isdetermined as a displacement amount. The relation between thedisplacement amount (shift amount) and the defocus amount as animage-plane moving amount is determined according to an optical system.Therefore, the defocus amount is calculated based on the displacementamount. Then, an extension amount of a lens is obtained based on thedefocus amount, and accordingly the lens can be moved to be focused.

Next, referring to FIG. 7, an AF control method performed by thecompound-eye image pickup apparatus 2 will be described. FIG. 7 is aflowchart of illustrating an image capturing operation (AF controlmethod) of the compound-eye image pickup apparatus 2. Each step in FIG.7 is performed by an instruction of the system controller 90 in thecompound-eye image pickup apparatus 2. In other words, the AF controlmethod illustrated in FIG. 7 can be realized as a program which causesthe system controller including a microcomputer (processor) to execute afunction of each step.

Steps S200 and S201 in FIG. 7 are similar to steps S100 and S101 inEmbodiment 1 (FIG. 5), respectively. Subsequently, at step S202, thesystem controller 90 calculates, via the phase-difference AF signalprocessor 33, a defocus amount by the phase-difference AF. For moredetails, the system controller 90 determines, as a focus detectionregion, an image center region or a region specified by a user via theinformation input unit 60. Then, the system controller 90 sets thephase-difference AF gate 32 so that only an image signal in thedetermined focus detection region is supplied to the phase-difference AFsignal processor 33.

The phase-difference AF signal processor 33 calculates the defocusamount by the correlation calculation described above. When a pluralityof lines are used as data, for example, the correlation calculation isperformed for each line and an average of the obtained correlation valuegroups can be obtained. Alternatively, the data of the plurality oflines may be averaged in upward and downward directions beforeperforming the correlation amount, and the averaged data may be used asdata for a single line to perform the correlation calculation. Thesystem controller 90 acquires the defocus amount which is calculated bythe phase-difference AF signal processor 33 based on the image signal inthe focus detection region.

Subsequently, at step S203, the system controller 90 outputs the defocusamount calculated at step S202 to the focus unit movement positioncalculator 52. The focus unit movement position calculator 52 calculatesa movement position of the focus unit 140 aF based on the defocusamount. Then, the system controller 90 moves, via the image pickupcontroller 50, the focus unit 140 aF to the calculated movementposition.

Subsequently, at step S204, the system controller 90 performs thephase-difference AF control again at the movement position of the focusunit 140 aF calculated at step S203, and it performs the in-focusdetermination. When the system controller 90 determines that the focusunit 140 aF is in the in-focus state as a result of the in-focusdetermination, the flow proceeds to step S205. On the other hand, whenthe system controller determines that the focus unit 140 aF is in theout-of-focus state, the flow returns to step S203. For more details,when the defocus amount calculated again is within a predeterminedthreshold value, the system controller 90 determines that the focus unit140 aF is in the in-focus state, and the flow proceeds to step S205. Onthe other hand, when the defocus amount is larger than the predeterminedthreshold value, the system controller 90 determines that the focus unit140 aF is in the out-of-focus state, and the flow returns to step S203.At step S205, the system controller 90 stops, via the image pickupcontroller 50, driving of the focus unit 140 aF at the position where itis determined that the focus unit 140 aF is in the in-focus state atstep S204.

Subsequent steps S206 and S207 are similar to steps S110 and S111 inEmbodiment 1 (FIG. 5), respectively. Thus, the AF control of thisembodiment is completed.

According to this embodiment, as an optical system to be used for AFcontrol, an optical system capable of determining a position of a focuslens with high accuracy can be selected. As a result, reduction of aprocessing load and improvement of focusing accuracy can be achieved inthe AF control.

Embodiment 3

Next, referring to FIG. 8, a compound-eye image pickup apparatus inEmbodiment 3 of the present invention will be described. FIG. 8 is ablock diagram of a compound-eye image pickup apparatus 3 in thisembodiment. The compound-eye image pickup apparatus 3 of this embodimentis different from the compound-eye image pickup apparatus 1 ofEmbodiment 1, the compound-eye image pickup apparatus 2 of Embodiment 2,or the combination of them in that the compound-eye image pickupapparatus 3 includes an information input unit 60 a containing a focusdetection region determiner 62 and a region inclusion determiner 63,instead of the information input unit 60.

The focus detection region determiner 62 (region determiner) determines,as a focus detection region, a region specified by a user via theinformation input unit 60 a. The region inclusion determiner 63(inclusion determiner) determines whether the focus detection region isincluded in each image signal obtained via an image pickup opticalsystem (imaging optical system) used for capturing an image.

Next, referring to FIG. 9, an AF control method performed by thecompound-eye image pickup apparatus 3 will be described. FIG. 9 is aflowchart of illustrating an image capturing operation (AF controlmethod) of the compound-eye image pickup apparatus 3. Each step in FIG.9 is performed by an instruction of the system controller 90 in thecompound-eye image pickup apparatus 3. In other words, the AF controlmethod illustrated in FIG. 9 can be realized as a program which causesthe system controller including a microcomputer (processor) to execute afunction of each step.

When the user inputs an image capturing signal (for example, when theuser presses a release button), the system controller 90 starts AFcontrol. When the AF control starts, at step S300, the system controller90 determines, as a focus detection region, the region specified by theuser via the information input unit 60 a. In this embodiment, the regionspecified by the user is determined as the focus detection region, butis not limited thereto. Simply, an image center region may be determinedas the focus detection region, or a plurality of regions set by defaultcan be determined as the focus detection region.

Subsequently, at step S301, the system controller 90 acquires an imagecapturing condition (image capturing condition information) from theinformation acquirer 61. The image capturing condition information isfor example imaging optical systems to be used for capturing an image,focal lengths of the imaging optical systems, Fno data, and diameters 6of permissible circles of confusion relating to pixel sizes of the imagepickup elements. Subsequently, at step S302, the region inclusiondeterminer 63 determines whether the image signal obtained via theimaging optical system to be used for capturing the image, acquired atstep S301, includes an image signal in the focus detection regiondetermined at step S300.

Subsequently, at step S303, the system controller 90 (imaging opticalsystem determiner 51) determines (selects) a first imaging opticalsystem from among the imaging optical systems for which it is determinedthat the focus detection region is included at step S302. In thisembodiment, the first imaging optical system is an imaging opticalsystem having the shallowest depth of field, which is selected based onthe focal length, the Fno data, and the diameter of the permissiblecircle of confusion as image capturing condition information. A methodof selecting the imaging optical system having the shallowest depth offield is the same as that of Embodiment 1. Subsequent steps S304 andS305 are similar to steps S202 and S203 in Embodiment 2 (FIG. 7).

Subsequently, at step S306, the system controller 90 performs, via theimage pickup controller 50, fine drive of the focus unit 140 aF at aposition of the focus unit to which the focus unit 140 aF is moved bythe phase-difference AF performed at steps S304 and S305. Subsequentsteps S307 to S315 are similar to steps S103 to S111 in Embodiment 1(FIG. 5).

As described above, the compound-eye image pickup apparatus of thisembodiment performs a rough adjustment by moving a focus unit up to thevicinity of a focal point by using focus detection (AF) by aphase-difference detection method, and subsequently it performs a fineadjustment by using an AF by a contrast detection method. Thus, focusdetection can be possible with high accuracy and in a short time.Furthermore, according to this embodiment, as an optical system to beused for AF control, an optical system capable of determining a positionof a focus lens with high accuracy can be selected. As a result,reduction of a processing load and improvement of focusing accuracy canbe achieved in the AF control.

Embodiment 4

Next, referring to FIG. 10, a compound-eye image pickup apparatus inEmbodiment 4 of the present invention will be described. FIG. 10 is ablock diagram of a compound-eye image pickup apparatus 4 in thisembodiment. The compound-eye image pickup apparatus 4 of this embodimentis different from the compound-eye image pickup apparatus 3 ofEmbodiment 3 in that the compound-eye image pickup apparatus 4 includesan image pickup unit 400 instead of the image pickup unit 100. Thecompound-eye image pickup apparatus 4 may be a lens-integrated imagepickup apparatus, or alternatively it can be configured by a lensapparatus including an imaging optical system (image pickup optical.system) and an image pickup apparatus body including an image pickupelement to which the lens apparatus is removably attached

Similarly to Embodiment 1 described referring to FIGS. 2 and 3, theimage pickup unit 400 includes eight imaging optical systems (imagepickup optical systems) 410 a, 420 a, 430 a, 440 a, 410 b, 420 b, 430 b,and 440 b, each of which forms an optical image of an object. The imagepickup unit 400 includes a plurality of image pickup elements thatcorrespond to the respective imaging optical systems 410 a to 440 b.FIG. 10 illustrates a cross section of the image pickup unit 400including optical axes OA1 and OA2 of the imaging optical systems 410 aand 440 a, respectively.

Each imaging optical system includes a focus unit F (focus lens unit orfront unit) and a rear unit R (fixed lens unit). As illustrated in FIG.10, the focus units F are held and driven integrally with a holder 300(holding member) so as to move by the same amount while an objectposition changes (i.e., while focusing is performed). The rear units Rare fixed by a holder 310 (holding member) during the focusing, andother members such as a stop (not illustrated) are included in eachimaging optical system. Thus, the compound-eye image pickup apparatus 4of this embodiment uses a partial focusing method in which parts of theoptical systems are moved integrally during the focusing. The number offocus lenses mounted on the focus unit F included in each imagingoptical system is one or more.

The plurality of image pickup elements 210 a to 210 f are heldintegrally and they constitute an image pickup element unit 200. Theimage pickup elements 210 a and 210 b correspond to the imaging opticalsystems 410 a and 420 a, respectively, and the image pickup elements 210c and 210 d correspond to the imaging optical systems 410 b and 420 b,respectively. The image pickup elements 210 e and 210 f correspond tothe imaging optical systems 440 a and 430 a, respectively, and the imagepickup elements 210 g and 210 h correspond to the imaging opticalsystems 440 b and 430 b, respectively.

Optical axes of the eight imaging optical systems 410 a, 420 a, 430 a,440 a, 410 b, 420 b, 430 b, and 440 b are approximately parallel to eachother. The two imaging optical systems (for example, imaging opticalsystems 410 a and 410 b) to which an identical reference numeral isadded has an identical focal length. In this embodiment, four pairs ofimaging optical systems 410, 420, 430, and 440 having focal lengthdifferent from each other are provided. The imaging optical systems 410a and 410 b are a pair of wide-angle imaging optical systems having theshortest focal length among the eight imaging optical systems. Theimaging optical systems 420 a and 420 b have a focal length longer thanthat of the imaging optical systems 410 a and 410 b. The imaging opticalsystems 430 a and 430 b have a focal length longer than that of theimaging optical systems 420 a and 420 b. The imaging optical systems 440a and 440 b have a focal length longer than that of the imaging opticalsystems 430 a and 430 b.

In FIG. 10, the imaging optical systems 410 a and 440 a constitute acompound eye. The image pickup elements 210 a and 210 e convert, toelectric signals (analog signals), optical images formed on surfaces(image pickup surfaces) of the image pickup elements 210 a and 210 e viathe imaging optical systems 410 a and 440 a, respectively.

Next, referring to FIG. 11, a focus drive mechanism of the image pickupunit 400 will be described. FIG. 11 is an enlarged perspective view of apart of the focus drive mechanism in the image pickup unit 400. Theholder 300 of the focus unit F includes a sleeve 403 which is fitted toand held by a first guide bar 401 disposed parallel to the optical axisof each imaging optical system, and a U-shaped groove 404 which isrotationally limited by a second guide bar 402. The image pickup unit400 includes an output axis 405 which rotates by an actuator such as astepping motor (not illustrated) and a rack member 406 which engageswith the output axis 405. Although a shape of the focus unit Fillustrated in FIG. 11 is different from that illustrated in FIG. 10,these shapes are one example and actually the shapes may be identical.As a result, the holder 300 which holds the focus units F includingparts of the plurality of imaging optical systems moves integrally in anoptical axis direction (directions of the optical axes OA1 and OA2indicated by dotted lines in FIG. 10) according to rotation of theoutput axis 405.

When in-focus images with different angles of field are intended to beacquired by using a compound-eye image pickup apparatus that has aplurality of imaging optical systems having focal lengths different fromeach other and the imaging optical systems are designed independently,it is necessary to provide a drive mechanism for each imaging opticalsystem since moving amounts of the focus units are different during thefocusing. For example, a drive motor is needed for each imaging opticalsystem, or components such as feed screws and gears having differentpitches are needed even if the drive motor can be shared. As a result,the size of the image pickup apparatus is enlarged, or the focus drivemechanism is complicated. In order to make the focus drive mechanism ina simple configuration, with respect to the plurality of imaging opticalsystems having focal lengths different from each other, the movingamounts of the focus units during the focusing need to be set to beidentical. As a unit for achieving it, as described in this embodiment,it is necessary to hold the focus units (focus lens units) by using acommon moving frame and the like, or hold integrally-molded focus units.

Referring to FIGS. 25 and 26, a paraxial arrangement of the opticalsystems for this purpose will be described. FIG. 25 is an explanatorydiagram of a movement of an image plane caused by variation of an objectdistance. FIG. 26 is an explanatory diagram of correction of the imageplane by moving the focus unit. According to Newton's equation, thefollowing expression (6) is satisfied where x is a distance from anobject-side focal point of the imaging optical system having a focallength f to an object (obj), and x′ is a distance from an image-sidefocal point to an image plane (img).

xx′=−f ²  (6)

According to expression (6), an image-plane moving amount Δx′, which isan amount obtained via the imaging optical system when the object ismoved by Δx, is represented by the following expression (7).

$\begin{matrix}{{\Delta \; x^{\prime}} = \frac{{{- f^{2}} \cdot \Delta}\; x}{x( {x + {\Delta \; x}} )}} & (7)\end{matrix}$

According to expression (7), an image-plane moving amount when avariation of an object distance occurs is proportional to the square ofthe focal length f of the imaging optical system. In other words, aratio of image-plane moving amounts Δx_(W)′ and Δx_(T)′ when thevariation of the object distance is Δx is represented by the followingexpression (8) where f_(W) and f_(T) are respectively focal lengths of awide-angle optical system (optical system W) and a telephoto opticalsystem (optical system T) illustrated in FIG. 25. Thus, the ratio of theimage-plane moving amounts Δx_(W)′ and Δx_(T)′ corresponds to a ratio ofthe squares of the respective focal lengths.

$\begin{matrix}{\frac{\Delta \; x_{T}^{\prime}}{\Delta \; x_{W}^{\prime}} = \frac{f_{T}^{2}}{f_{W}^{2}}} & (8)\end{matrix}$

According to expression (8), as illustrated in FIG. 25, when anidentical object is imaged by using optical systems having focal lengthsdifferent from each other, the image-plane moving amounts Δx_(T)′ of thetelephoto optical system moves the ratio of the squares of the focallengths times as large as the image-plane moving amounts Δx_(W)′ of thewide-angle optical system (Δx_(T)′=Δx_(W)′·f_(T) ²/f_(W) ²).

A focusing method in which an in-focus image is formed on a sensorsurface by moving an entire optical system depending on an objectdistance is known as an entire extension. When the focusing is performedby extending each of the entire optical systems, an extension amount ofthe optical system and a variation amount of the image plane have aone-to-one relationship. Therefore, the extension amount of each of theentire optical systems for forming an image on the sensor surface isidentical to each of Δx_(W)′ and Δx_(T)′. In other words, the telephotooptical system needs to extend a ratio of squares of focal lengths timesas large as the wide-angle optical system, and accordingly it isdifficult to drive them integrally and a drive mechanism is needed foreach optical system, which results in a complicated focus drivemechanism.

In this embodiment, as illustrated in FIG. 26, a partial focusing methodin which a part of the optical systems is moved during the focusing isadopted. As partial focusing methods of lenses, a front lens focus typein which a first lens unit disposed at the object side is moved, and aninner focus type and a rear focus type in which a lens unit subsequentto a second lens unit is moved are known. A position sensitivity ES withrespect to a variation of the image plane caused by the movement of thefocus unit F in the optical axis direction is represented by thefollowing expression (9) where β_(F) is a lateral magnification of thefocus unit and β_(R) is a lateral magnification of the image-side unit Rdisposed at the image side relative to the focus unit.

ES=(1−β_(F) ²)·β_(R) ²  (9)

When a lens unit does not exist at the image side relative to the focusunit as is the case for the rear focus type, the lateral magnificationβ_(R) is 1 and the position sensitivity ES is ES=1−β_(F) ². A movingamount ΔA′ of the image plane caused by the movement of the focus unitis represented by the following expression (10) where ΔA is a movingamount of the focus unit during the focusing.

ΔA′=ΔA·ES  (10)

In other words, in order to perform the partial focusing method, themoving amount Δx′ of the image plane caused by the variation of theobject distance represented by expression (7) and the moving amount ΔA′of the image plane caused by the moving amount AA of the focus unitrepresented by expression (10) only have to be equal to each other. As aresult, in order to correct the variation of the image plane by themoving amount Δx′ in the optical system including the focus unit havinga certain position sensitivity ES, the focus unit only has to be movedby AA represented by the following expression (11).

$\begin{matrix}{{\Delta \; A} = \frac{\Delta \; x^{\prime}}{ES}} & (11)\end{matrix}$

In this embodiment, focal lengths of the wide-angle optical system(optical system W) and the telephoto optical system (optical system T)illustrated in FIG. 26 are denoted by f_(W) and f_(T), respectively, alateral magnification of the focus unit in the optical system W isdenoted by β_(FW), a lateral magnification of the image-side unit in theoptical system W is denoted by β_(RW), a lateral magnification of thefocus unit in the optical system T is denoted by β_(FT), and a lateralmagnification of the focus unit in the optical system T is denoted byβ_(RT). In this case, position sensitivities ES_(W) and ES_(T) of thefocus unit in the optical systems W and T are represented by thefollowing expressions (12) and (13), respectively.

ES _(W)=(1−β_(FW) ²)·β_(RW) ²  (12)

ES _(T)=(1−β_(FT) ²)·β_(RT) ²  (13)

A conditional expression to be used for performing the image-planecorrection of the moving amounts Δx_(W)′ and Δx_(T)′ of the image planescaused by the moving amounts Δx of an object illustrated in FIGS. 19Aand 19B by using the moving amount ΔA (identical moving amount) of thefocus units is represented by the following expression (14) according toexpressions (11) to (13).

$\begin{matrix}{{\Delta \; A} = {\frac{\Delta \; x_{W}^{\prime}}{{ES}_{W}} = \frac{\Delta \; x_{T}^{\prime}}{{ES}_{T}}}} & (14)\end{matrix}$

According to expression (8), expression (14) is represented by thefollowing expression (15).

$\begin{matrix}{\frac{{ES}_{W}^{\prime} \cdot f_{T}^{2}}{{ES}_{T} \cdot f_{W}^{2}} = 1} & (15)\end{matrix}$

Expression (15) is a paraxial conditional expression that is to besatisfied to make the moving amounts of the focus units identical inoptical systems having focal lengths different from each other. In theoptical system of this embodiment, the lateral magnification of thefocus unit F and the image-side unit (rear unit R) is set so as tosatisfy expression (15). Expression (15) indicates that the movingamounts for the focusing can be identical when a ratio of the squares ofthe focal lengths and a ratio of the position sensitivities of the focusunits are approximately the same in the optical systems having the focallengths different from each other.

The position sensitivity of the focus unit does not have to satisfyexpression (15) completely if a defocus amount is within a diameter δ ofa permissible circle of confusion. For example, when a differencebetween the moving amount Δx′ of the image plane and the moving amountΔA′ of the image plane caused by the focus unit is defined as a defocusamount and the diameter δ of the permissible circle of confusion isapproximately from 1/500 to 1/1000 of an image pickup surface (imagecircle), the defocus amount only has to satisfy the following expression(16).

|Δx′−ΔA′|<(F number)×δ  (16)

Accordingly, in an actual optical system, the defocus amount is within adepth of focus of the optical system if the following expression (17) issatisfied, and the in-focus images can be acquired at the same time byan identical moving amount of the focus units.

$\begin{matrix}{0.8 < \frac{{ES}_{W} \cdot f_{T}^{2}}{{ES}_{T} \cdot f_{W}^{2}} < 1.2} & (17)\end{matrix}$

In other words, in order to acquire the in-focus images having differentangles of field at the same time with a simple focus drive mechanism, itis necessary to integrally hold the focus units of the respectiveoptical systems having different focal lengths and also to satisfyexpression (17) to make the moving amounts for the focusing identical.Accordingly, each focus unit in this embodiment satisfies expression(17) to make the moving amount for the focusing identical in theplurality of imaging optical systems having different focal lengths.

Next, referring to FIG. 12, an AF control method performed by thecompound-eye image pickup apparatus 4 will be described. FIG. 12 is aflowchart of illustrating an image capturing operation (AF controlmethod) of the compound-eye image pickup apparatus 4. Each step in FIG.12 is performed by an instruction of the system controller 90 in thecompound-eye image pickup apparatus 4. In other words, the AF controlmethod illustrated in FIG. 12 can be realized as a program which causesthe system controller including a microcomputer (processor) to execute afunction of each step.

Steps S400 to S404 in FIG. 12 are the same as steps S300 to S304 inEmbodiment 3 (FIG. 9), respectively. Subsequently, at step S405, thesystem controller 90 sends the defocus amount calculated at step S404 tothe focus unit movement position calculator 52 to calculate a movementposition. Then, the system controller 90 moves, via the image pickupcontroller 50, the focus units integrally to the calculated movementposition. Subsequent steps S406 to S412 are the same as steps S306 toS312 in Embodiment (FIG. 9), except for controlling the movements of thefocus units integrally.

In this embodiment, a plurality of imaging optical systems having focallengths different from each other satisfy expression (17) that isnecessary for making moving amounts for focusing identical. Accordingly,for an identical object distance, all the imaging optical systems alwaysfocus on an object while all the focus units move by the identicalmoving amount. In this configuration of the imaging optical systems, theprocess of calculating the positions of the focus units in the imagingoptical systems other than the selected imaging optical system can beomitted, and accordingly the AF control can be performed moreefficiently. This embodiment describes the case where the AF control isperformed efficiently by adopting the imaging optical systems having theidentical focus moving amount on the basis of the configuration inEmbodiment 3, and similarly this embodiment can be configured on thebasis of the configuration in Embodiment 1 or 2.

Next, first to fourth compound-eye optical systems which can be adoptedto the compound-eye image pickup apparatus 4 of this embodiment will bedescribed. The compound-eye optical systems of this embodiment adopt apartial focusing method in at least one imaging optical system, whichsatisfy conditional expression (17). Accordingly, the plurality ofimaging optical systems having focal lengths different from each otherhave an identical moving amounts for focusing. Specifically, lateralmagnifications β_(F) and β_(R), which impact on a position sensitivityES of the focus unit F, of the focus unit F of each optical system andthe image-side unit (rear unit R) disposed at the image side relative tothe focus unit F, respectively, are appropriately set.

With respect to a calculation condition of the conditional expression inthis case, a focal length and a position sensitivity of the opticalsystem having the largest focal length in each compound-eye opticalsystem are substituted in f_(T) and ES_(FT) in conditional expression(17). In addition, a focal length and a position sensitivity of thetarget imaging optical system are substituted in f_(T) and ES_(FT) inconditional expression (17). When each optical system satisfiesconditional expression (17) in this calculation condition, all facetoptical systems can focus on an identical object on condition that amoving amount of a focus unit are set to that of a tele facet having theshallowest depth of focus.

Furthermore, a lens is disposed to be approximately the same as a lensconstituting the other optical system adjacent in a vertical directionof each optical axis so as to be easily hold the lenses integrally. Inaddition, each lens is made of an identical material to the lensconstituting the other optical system adjacent in the vertical directionof each optical axis so as to mold them integrally. As a method of theintegral molding, for example, a conventional injection molding methodor glass molding method in which a glass is disposed in a mold and thenpressed can be used. Positions of front lenses in the respective opticalsystems are set to be approximately the same so that light beams of eachoptical system do not interfere with those of the other optical systems.Positions of image planes (image pickup regions) are set to beapproximately the same so that an arrangement or an adjustment of theimage pickup element is easy. A surface shape of a lens constitutingeach optical system is different from a lens constituting the otheroptical system adjacent in the vertical direction of each optical axis.Even when the lenses having different surface shapes and being made ofan identical material, sufficient optical imaging performance can beachieved. Furthermore, in order to achieve a sufficient high zoom ratio(variable magnification ratio) as an image pickup apparatus, a ratio offocus lengths of the wide facet and the tele facet is one-and-a-halftimes or more.

FIGS. 13A to 13D are cross-sectional views of lenses of a wide facet, awide-middle facet, a tele-middle facet, and a tele facet in the firstcompound-eye optical system, respectively. In the first compound-eyeoptical system, the focus unit F moves to an object side and theimage-side unit (rear unit R) is fixed during the focusing from anobject at infinity to an object in a close range (front lens focustype). FIGS. 14A to 14D are aberration diagrams of the wide,wide-middle, tele-middle, and tele in Numerical example 1 correspondingto the first compound-eye optical system, respectively.

FIGS. 15A to 15D are cross-sectional views of lenses of a wide facet, awide-middle facet, a tele-middle facet, and a tele facet in the secondcompound-eye optical system, respectively. In the second compound-eyeoptical system, the focus unit F moves to the object side and theimage-side unit (rear unit R) is fixed during the focusing from theobject at infinity to the object in the close range (inner focus type).FIGS. 16A to 16D are aberration diagrams of the wide, wide-middle,tele-middle, and tele in Numerical example 2 corresponding to the secondcompound-eye optical system, respectively.

FIGS. 17A to 17D are cross-sectional views of lenses of a wide facet, awide-middle facet, a tele-middle facet, and a tele facet in the thirdcompound-eye optical system, respectively. In the third compound-eyeoptical system, the focus unit F moves to the object side during thefocusing from the object at infinity to the object in the close rangeand the image-side unit (rear unit R) does not exist (rear focus type).FIGS. 18A to 18D are aberration diagrams of the wide, wide-middle,tele-middle, and tele in Numerical example 3 corresponding to the thirdcompound-eye optical system, respectively.

FIGS. 19A and 19B are cross-sectional views of lenses of a wide facetand a tele facet in the fourth compound-eye optical system,respectively. In the fourth compound-eye optical system, the focus unitF moves to the object side during the focusing from the object atinfinity to the object in the close range. In the wide facet, theimage-side unit (rear unit Rha) is fixed during the focusing, and in thetele facet, the image-side unit (rear unit R) does not exist. In otherwords, a front lens focus type for the wide facet and an entireextension type for the tele facet are adopted as a focus type. Asdescribed above, conditional expression (17) can be satisfied if one isthe entire extension type and the other is a partial focus type.

FIGS. 20A and 20B are aberration diagrams of the wide and tele inNumerical example 4 corresponding to the fourth compound-eye opticalsystem, respectively. In each cross-sectional view of lenses, the leftside is an object side, i.e., object side (front side), and the rightside is an image side (rear side). Symbol F denotes a focus unit, symbolR denotes an image-side unit (rear unit), symbol SP denotes an aperturestop, and symbol IP denotes an image plane. The image plane IPcorresponds to an image pickup surface of a solid-state image pickupelement (photoelectric conversion element) such as a CCD sensor and aCMOS sensor. It corresponds to a film surface if a silver salt film isused. In each aberration diagram, symbols d and g denote d-line andg-line, respectively, and symbols ΔM and ΔS denote a meridional imagesurface and a sagittal image surface, respectively. A chromaticaberration of magnification is represented by the g-line. Symbol codenotes a half angle of field, and symbol Fno denotes an F number.

The image pickup unit 400 in this embodiment is simply constituted bytwo lenses of the focus unit F and the image-side unit (rear unit R).However, this embodiment is not limited thereto, and a holder or adriver of the focus unit may be configured appropriately according tothe optical system in each of Numerical examples 1 to 4.

As described above, a control apparatus in each embodiment includes afocus detector (AF signal processor or phase-difference AF signalprocessor 33) and a controller (image pickup controller 50). The focusdetector performs focus detection based on an image signal (focalsignal, or output signal from an image pickup element) obtained via afirst optical system (first imaging optical system) having a shallowestdepth of field in a plurality of optical systems (imaging opticalsystems) having focal lengths different from each other. The controllerperforms focus control of the plurality of optical systems based on anoutput signal from the focus detector. Each of the focus detector andthe controller operates based on an instruction of the system controller(camera CPU or lens CPU).

Preferably, the control apparatus includes a calculator (focus unitmovement position calculator 52) which calculates a movement position ofa focus lens of a second optical system (optical systems other than thefirst optical system) in the plurality of optical systems. Thecontroller performs the focus control by moving a focus lens of thefirst optical system based on the output signal from the focus detector.Then, the calculator calculates the movement position of the focus lensof the second optical system based on a position of the focus lens ofthe first optical system. Preferably, the controller performs the focuscontrol by integrally moving a plurality of focus lenses of theplurality of optical systems by an identical moving amount based on theoutput signal from the focus detector.

Preferably, the control apparatus includes an acquirer (informationacquirer 61) which acquires image capturing condition information and adeterminer (imaging optical system determiner 51) which determines thefirst optical system based on the image capturing condition information.More preferably, the acquirer acquires, as the image capturing conditioninformation, information relating to the plurality of optical systems,focal lengths of the optical systems, and F numbers of the opticalsystems. Then, the determiner determines the first optical systemsatisfying conditional expression (3a) where f₁ is a focal length of thefirst optical system, Fno₁ is an F number of the first optical system,f_(i) is a focal length of one of the optical systems, and Fno_(i) is anF number of the one of the optical systems.

Preferably, the focus detector performs the focus detection by acontrast detection method or a phase-difference detection method.Preferably, the focus detector includes a first focus detector(phase-difference AF signal processor 33) which performs focus detectionby a phase-difference detection method and a second focus detector (AFsignal processor 31) which performs focus detection by a contrastdetection method. Then, the controller performs first focus controlbased on a first output signal from the first focus detector. Thecontroller performs second focus control based on a second output signalfrom the second focus detector after the first focus control.

Preferably, the control apparatus includes a region determiner (focusdetection region determiner 62) and an inclusion determiner (regioninclusion determiner 63). The region determiner determines a region inwhich the focus detection is to be performed. The inclusion determinerdetermines whether the region determined by the region determiner isincluded in an image pickup region for each of the plurality of opticalsystems. Then, the determiner determines the first optical system basedon a determination result of the inclusion determiner.

An image pickup apparatus of each embodiment (each of compound-eye imagepickup apparatuses 1 to 4) includes the control apparatus and an imagepickup element (image pickup element unit 200) which photoelectricallyconverts an optical image formed via a plurality of optical systemshaving focal lengths different from each other. Preferably, the imagepickup element includes a plurality of image pickup regions (imagepickup elements 210 a to 210 h) corresponding to the respective opticalsystems.

An image pickup system of each embodiment (each of compound-eye imagepickup apparatuses 1 to 4) includes the image pickup apparatus and aplurality of optical systems (imaging optical systems 110 to 140 or 410to 440) having focal lengths different from each other. Preferably, theplurality of optical systems include at least two optical systems (forexample, imaging optical systems 110 a and 110 b) having an identicalfocal length. Preferably, the image pickup system includes a holder(holder 300) which integrally moves a plurality of focus lenses of theoptical systems by an identical moving amount during the focus controlof the optical systems.

A lens apparatus of each embodiment includes the plurality of opticalsystems (imaging optical systems 110 to 140 or 410 to 440) and thecontroller (system controller 90). The controller performs focus controlof the plurality of optical systems based on an image signal obtainedvia a first optical system having a shallowest depth of field in theplurality of optical systems. In this case, the controller is includedin the lens apparatus and it has a function which is similar to that ofthe image pickup controller 50.

Other Embodiments

Embodiment (s) of the present invention can also be realized by acomputer of a system or apparatus that reads out and executes computerexecutable instructions (e.g., one or more programs) recorded on astorage medium (which may also be referred to more fully as a‘non-transitory computer-readable storage medium’) to perform thefunctions of one or more of the above-described embodiment(s) and/orthat includes one or more circuits (e.g., application specificintegrated circuit (ASIC)) for performing the functions of one or moreof the above-described embodiment(s), and by a method performed by thecomputer of the system or apparatus by, for example, reading out andexecuting the computer executable instructions from the storage mediumto perform the functions of one or more of the above-describedembodiment(s) and/or controlling the one or more circuits to perform thefunctions of one or more of the above-described embodiment(s). Thecomputer may comprise one or more processors (e.g., central processingunit (CPU), micro processing unit (MPU)) and may include a network ofseparate computers or separate processors to read out and execute thecomputer executable instructions. The computer executable instructionsmay be provided to the computer, for example, from a network or thestorage medium. The storage medium may include, for example, one or moreof a hard disk, a random-access memory (RAM), a read only memory (ROM),a storage of distributed computing systems, an optical disk (such as acompact disc (CD), digital versatile disc (DVD), or Blu-ray Disc (BD)™),a flash memory device, a memory card, and the like.

While the present invention has been described with reference toexemplary embodiments, it is to be understood that the invention is notlimited to the disclosed exemplary embodiments. The scope of thefollowing claims is to be accorded the broadest interpretation so as toencompass all such modifications and equivalent structures andfunctions.

The following numerical examples 1 to 4 are specific numerical datacorresponding to the first to fourth compound-eye optical systems,respectively. In each numerical example, symbol i denotes the number ofa surface counted from the object side. Symbol ri denotes a radius ofcurvature of an i-th optical surface (i-th surface). Symbol di denotes adistance on the optical axis between an i-th surface and an (i+1)-thsurface. Symbols ndi and vdi denote a refractive index and the Abbenumber of a material of an i-th optical member for the d-line,respectively. Symbol f denotes a focal length, symbol Fno denotes an Fnumber, and symbol ω denotes a half angle of field. The distance d ofzero (d=0) means that adjacent surfaces are cemented (joined)

An aspherical shape is given by the following expression (18) wheresymbol R denotes a radius of curvature, and K, A3, A4, A5, A6, A7, A8,A9, A10, A11, and A12 denote aspherical coefficients.

X=(H ² /R)/[1+{1−(1+K)(H/R)²}^(1/2) ]+A3·H ³ +A4·H ⁴ +A5·H ⁵ +A6·H ⁶+A7·H ⁷ +A8·H ⁸ +A9·H ⁹ +A10·H ¹⁰ +A11·H ¹¹ +A12·H ¹²  (18)

Symbol “e±XX” for each aspherical coefficient means “×10^(±xx)”.

Table 1 indicates a relationship between conditional expression (17) andeach of numerical examples 1 to 4 (Embodiments 1 to 4). Each of thefocal length, the F number, and the angle of field represents a valuewhen focusing on an object at infinity. Symbol BF is an air-convertedvalue of a distance from a final lens surface to an image plane.

(NUMERICAL EXAMPLE 1) Wide facet Unit mm Surface data Surface number r dnd νd  1* 40.382 1.30 1.62041 60.3  2* 2.411 2.67  3* 6.203 1.40 1.5924068.3  4* −11.433 0.50  5* −62.116 0.80 1.80518 25.4  6* 15.255 0.10 7(stop) ∞ 0.10  8* 6.018 1.20 1.64000 60.1  9* −12.756 3.48 10* 9.9281.80 1.59240 68.3 11* −11.658 0.50 12* −28.136 1.00 1.84666 23.8 13*8.934 Image plane ∞ Aspherical data 1st surface K = −8.61567e+001 A 4 =−9.22230e−004 A 6 = 4.19663e−005 2nd surface K = −9.30223e−001 A 4 =7.19408e−003 A 6 = 6.36185e−004 3rd surface K = 3.54414e+000 A 4 =2.81499e−003 A 6 = 2.34019e−004 4th surface K = −3.53906e+000 A 4 =1.43935e−003 A 6 = 1.07092e−004 5th surface K = 3.15676e+000 A 4 =1.79932e−003 A 6 = −9.65503e−004 6th surface K = 4.96423e+001 A 4 =1.09416e−003 A 6 = −7.97966e−004 8th surface K = −3.06847e+000 A 4 =−1.51330e−004 A 6 = 3.84651e−004 9th surface K = 9.75797e+000 A 4 =−3.28928e−004 A 6 = 5.50566e−004 10th surface K = −1.10481e+001 A 4 =2.90917e−004 A 6 = 5.26599e−004 11th surface K = 1.72650e+001 A 4 =−4.08824e−003 A 6 = 9.11055e−004 12th surface K = −7.35482e+001 A 4 =−1.54275e−002 A 6 = 3.85072e−004 13th surface K = 7.43385e+000 A 4 =−1.07701e−002 A 6 = 4.92519e−004 Various data Focal length 5.20 F number2.88 Half angle of field 36.69 Image height 3.88 Total lens length 17.91BF 3.06 Entrance pupil position 3.15 Exit pupil position −4.86Front-side principal point position 4.94 Rear-side principal pointposition −2.14 Single lens data Lens Start surface Focal length 1 1−4.19 2 3 6.99 3 5 −15.14 4 8 6.55 5 10 9.34 6 12 −7.91 Wide-middlefacet Unit mm Surface data Surface number r d nd νd  1* 6.194 1.301.62041 60.3  2* 2.200 2.67  3* 6.346 1.40 1.59240 68.3  4* −26.449 0.50 5* −41.518 0.80 1.80518 25.4  6* 14.348 0.10  7(stop) ∞ 0.10  8* 4.9791.20 1.64000 60.1  9* −7.878 3.48 10* −7.653 1.80 1.59240 68.3 11*−7.611 0.50 12* −12.407 1.00 1.84666 23.8 13* 52.342 Image plane ∞Aspherical data 1st surface K = −5.86699e+000 A 4 = −8.96118e−004 A 6 =1.23087e−006 2nd surface K = −1.11462e+000 A 4 = 5.18382e−003 A 6 =7.47793e−004 3rd surface K = 2.23083e+000 A 4 = 2.29189e−003 A 6 =9.11689e−005 4th surface K = 3.98608e+001 A 4 = −1.07969e−003 A 6 =−1.03444e−004 5th surface K = −2.66134e+001 A 4 = 2.91291e−004 A 6 =−5.80559e−004 6th surface K = 3.25993e+001 A 4 = 1.05064e−003 A 6 =−3.89850e−004 8th surface K = −3.31035e+000 A 4 = 9.36039e−004 A 6 =4.48060e−005 9th surface K = 1.62170e+000 A 4 = −1.30807e−004 A 6 =1.97962e−004 10th surface K = −1.84308e+001 A 4 = −9.71624e−003 A 6 =5.68105e−004 11th surface K = −2.88780e+001 A 4 = −1.01570e−002 A 6 =1.38466e−004 12th surface K = −9.00000e+001 A 4 = −1.47730e−002 A 6 =−1.20913e−005 13th surface K = −5.42659e+001 A 4 = −8.67083e−003 A 6 =3.90008e−004 Various data Focal length 7.50 F number 2.88 Half angle offield 27.32 Image height 3.88 Total lens length 17.91 BF 3.06 Entrancepupil position 4.05 Exit pupil position −4.94 Front-side principalposition 4.52 Rear-side principal position −4.44 Single lens data LensStart surface Focal length 1 1 −6.28 2 3 8.78 3 5 −13.16 4 8 4.95 5 10138.07 6 12 −11.76 Tele-middle facet Unit mm Surface data Surface numberr d nd νd  1* −14.915 1.30 1.62041 60.3  2* 69.090 2.67  3* 5.672 1.401.59240 68.3  4* −7.487 0.50  5* −9.447 0.80 1.80518 25.4  6* −22.1000.10  7(stop) ∞ 0.10  8* 3.929 1.20 1.64000 60.1  9* 2.484 3.48 10*6.037 1.80 1.59240 68.3 11* 21.097 0.50 12* 13.374 1.00 1.84666 23.8 13*6.940 Image plane ∞ Aspherical data 1st surface K = 3.23218e+000 A 4 =−3.05400e−004 A 6 = 4.53521e−005 2nd surface K = −9.00000e+001 A 4 =1.59130e−004 A 6 = 5.15981e−005 3rd surface K = −1.64767e+000 A 4 =2.27739e−003 A 6 = −6.09668e−006 4th surface K = −7.51140e+000 A 4 =2.83658e−004 A 6 = 7.41960e−005 5th surface K = 8.77500e+000 A 4 =1.90647e−004 A 6 = 7.09546e−004 6th surface K = 7.06211e+000 A 4 =−1.29880e−003 A 6 = 6.54962e−004 8th surface K = −7.69118e−001 A 4 =−1.53255e−003 A 6 = −1.23634e−004 9th surface K = −9.82229e−001 A 4 =2.51720e−004 A 6 = −1.95089e−004 10th surface K = −4.39310e+000 A 4 =2.05043e−003 A 6 = −1.72957e−005 11th surface K = 3.04604e+001 A 4 =9.28199e−004 A 6 = −1.81115e−004 12th surface K = 5.49088e+000 A 4 =−1.18023e−003 A 6 = 3.43330e−005 13th surface K = 2.34608e+000 A 4 =−3.33103e−003 A 6 = 1.61864e−004 Various data Focal length 10.50 Fnumber 2.88 Half angle of field 20.26 Image height 3.88 Total lenslength 17.91 BF 3.06 Entrance pupil position 4.64 Exit pupil position−5.12 Front-side principal position 1.66 Rear-side principal position−7.44 Single lens data Lens Start surface Focal length 1 1 −19.66 2 35.67 3 5 −21.09 4 8 −15.62 5 10 13.67 6 12 −18.35 Tele facet Unit mmSurface data Surface number r d nd νd  1* 36.807 1.30 1.62041 60.3  2*−41.677 2.67  3* 8.270 1.40 1.59240 68.3  4* −7.910 0.50  5* −9.885 0.801.80518 25.4  6* −54.358 0.10  7(stop) ∞ 0.10  8* 5.124 1.20 1.6400060.1  9* 2.412 3.48 10* 10.272 1.80 1.59240 68.3 11* 16.743 0.50 12*9.281 1.00 1.84666 23.8 13* 10.176 Image plane ∞ Aspherical data 1stsurface K = −9.00000e+001 A 4 = 3.25623e−005 A 6 = 1.37046e−005 2ndsurface K = 6.54916e+001 A 4 = 9.61894e−004 A 6 = 1.97095e−005 3rdsurface K = −5.20341e−001 A 4 = 2.82359e−003 A 6 = 1.62204e−005 4thsurface K = −1.07451e+001 A 4 = 1.35610e−003 A 6 = −1.75272e−005 5thsurface K = 9.36306e+000 A 4 = 3.65867e−003 A 6 = 3.57432e−004 6thsurface K = −1.69149e+001 A 4 = 1.12483e−003 A 6 = 6.25155e−004 8thsurface K = −6.38373e−001 A 4 = −3.54965e−003 A 6 = 1.25622e−006 9thsurface K = −9.28207e−001 A 4 = −1.83232e−003 A 6 = −1.58220e−004 10thsurface K = 6.03894e−001 A 4 = 1.13103e−003 A 6 = 4.35985e−005 11thsurface K = −8.36796e+000 A 4 = 9.48431e−004 A 6 = −5.05453e−005 12thsurface K = −2.24043e+000 A 4 = −9.07528e−004 A 6 = 9.61281e−007 13thsurface K = 6.10242e+000 A 4 = −2.60010e−003 A 6 = 1.92825e−005 Variousdata Focal length 15.00 F number 2.88 Half angle of field 14.48 Imageheight 3.88 Total lens length 17.91 BF 3.06 Entrance pupil position 6.90Exit pupil position −6.27 Front-side principal position −2.20 Rear-sideprincipal position −11.94 Single lens data Lens Start surface Focallength 1 1 31.71 2 3 7.05 3 5 −15.13 4 8 −8.61 5 10 40.66 6 12 82.43

(NUMERICAL EXAMPLE 2) Wide facet Unit mm Surface data Surface number r dnd νd  1* −42.834 1.30 1.72916 54.7  2* 3.863 1.95  3* 10.061 1.401.59240 68.3  4* −254.805 0.97  5(stop) ∞ 0.20  6* 60.619 0.80 1.8051825.4  7* 15.022 0.20  8* 12.585 1.20 1.64000 60.1  9* −6.869 1.35 10*6.405 1.80 1.59240 68.3 11* −9.227 1.28 12* 42.308 1.00 1.84666 23.8 13*4.861 Image plane ∞ Aspherical data 1st surface K = −9.00000e+001 A 4 =1.68209e−003 A 6 = 2.18378e−005 2nd surface K = 1.56201e+000 A 4 =2.31919e−004 A 6 = 2.49857e−005 3rd surface K = 1.56344e+001 A 4 =−2.30989e−003 A 6 = −3.90307e−004 4th surface K = −9.00000e+001 A 4 =8.76797e−004 A 6 = −3.09096e−004 6th surface K = −9.00000e+001 A 4 =7.22417e−004 A 6 = 1.69814e−004 7th surface K = −5.28938e+001 A 4 =3.20245e−003 A 6 = 2.63310e−004 8th surface K = −3.31531e+001 A 4 =3.32480e−003 A 6 = −1.76152e−005 9th surface K = −1.14135e+000 A 4 =−8.15775e−004 A 6 = 3.19305e−006 10th surface K = −8.67401e+000 A 4 =2.26418e−003 A 6 = −3.63267e−004 11th surface K = 2.68548e+000 A 4 =−2.16758e−003 A 6 = −4.66522e−005 12th surface K = 9.00000e+001 A 4 =−8.67976e−003 A 6 = 6.91067e−004 13th surface K = −5.35623e+000 A 4 =9.73749e−004 A 6 = 7.24657e−004 Various data Focal length 5.20 F number2.88 Half angle of field 36.69 Image height 3.88 Total lens length 18.00BF 4.55 Entrance pupil position 2.89 Exit pupil position −4.03Front-side principal point 4.94 Rear-side principal point −0.65 Singlelens data Lens Start surface Focal length 1 1 −4.80 2 3 16.37 3 6 −25.004 8 7.11 5 10 6.67 6 12 −6.57 Wide-middle facet Unit mm Surface dataSurface number r d nd νd  1* 7.207 1.30 1.72916 54.7  2* 4.000 1.95  3*7.876 1.40 1.59240 68.3  4* 4.755 0.97  5(stop) ∞ 0.20  6* 11.962 0.801.80518 25.4  7* 5.782 0.20  8* 7.462 1.20 1.64000 60.1  9* −5.083 1.3510* 4.011 1.80 1.59240 68.3 11* 7.357 1.28 12* 12.505 1.00 1.84666 23.813* 5.927 Image plane ∞ Aspherical data 1st surface K = −4.55173e+000 A4 = 1.04524e−003 A 6 = 5.22673e−005 2nd surface K = 1.07655e+000 A 4 =−2.68944e−003 A 6 = 1.76360e−004 3rd surface K = −5.98889e+000 A 4 =−7.72514e−003 A 6 = 4.93606e−004 4th surface K = −6.75596e+000 A 4 =−4.98007e−003 A 6 = 5.07961e−004 6th surface K = −7.89069e+001 A 4 =−2.69850e−003 A 6 = 3.52609e−004 7th surface K = −2.27576e+001 A 4 =1.42455e−003 A 6 = −1.01831e−005 8th surface K = −3.33768e+001 A 4 =4.50455e−003 A 6 = −2.18686e−004 9th surface K = −2.68795e−002 A 4 =−2.95824e−004 A 6 = 1.05748e−004 10th surface K = −2.20833e+000 A 4 =3.37019e−003 A 6 = 3.11853e−005 11th surface K = 1.71227e+000 A 4 =−4.49146e−005 A 6 = 1.17908e−004 12th surface K = 5.70869e−001 A 4 =−3.54385e−003 A 6 = 2.46582e−004 13th surface K = −1.78719e+000 A 4 =−7.83362e−004 A 6 = 3.59345e−004 Various data Focal length 7.50 F number2.88 Half angle of field 27.32 Image height 3.88 Total lens length 18.00BF 4.55 Entrance pupil position 4.41 Exit pupil position −4.23Front-side principal position 5.51 Rear-side principal position −2.95Single lens data Lens Start surface Focal length 1 1 −14.87 2 3 −24.32 36 −14.75 4 8 4.91 5 10 12.41 6 12 −14.31 Tele-middle facet Unit mmSurface data Surface number r d nd νd  1* −15.000 1.30 1.72916 54.7  2*17.960 1.95  3* 6.796 1.40 1.59240 68.3  4* −7.146 0.97  5(stop) ∞ 0.20 6* −14.236 0.80 1.80518 25.4  7* −98.169 0.20  8* 5.334 1.20 1.6400060.1  9* 4.199 1.35 10* 5.372 1.80 1.59240 68.3 11* 9.899 1.28 12* 5.1281.00 1.84666 23.8 13* 3.875 Image plane ∞ Aspherical data 1st surface K= 8.00699e+000 A 4 = −1.47327e−003 A 6 = 7.30169e−005 2nd surface K =−3.65224e+001 A 4 = −5.44314e−004 A 6 = 5.29084e−005 3rd surface K =−3.27830e+000 A 4 = 9.82143e−004 A 6 = 1.93818e−005 4th surface K =−1.26439e+000 A 4 = 1.25692e−003 A 6 = −7.42342e−006 6th surface K =−5.37243e+000 A 4 = 1.00930e−003 A 6 = 8.59265e−005 7th surface K =−9.00000e+001 A 4 = 2.44487e−003 A 6 = 1.02366e−004 8th surface K =−5.01056e+000 A 4 = 8.62296e−003 A 6 = 6.49491e−005 9th surface K =6.14970e−001 A 4 = 2.64291e−003 A 6 = 4.35217e−004 10th surface K =7.18277e−001 A 4 = 3.35315e−003 A 6 = −1.54486e−004 11th surface K =1.51189e+000 A 4 = 5.61145e−003 A 6 = −1.70734e−004 12th surface K =9.04194e−001 A 4 = −6.62979e−003 A 6 = −1.55750e−004 13th surface K =−6.57254e−003 A 4 = − 9.21593e−003 A 6 = 2.82444e−005 Various data Focallength 10.50 F number 2.88 Half angle of field 20.26 Image height 3.88Total lens length 18.00 BF 4.55 Entrance pupil position 3.62 Exit pupilposition −4.01 Front-side principal position 1.25 Rear-side principalposition −5.95 Single lens data Lens Start surface Focal length 1 1−11.03 2 3 6.11 3 6 −20.77 4 8 −52.55 5 10 17.27 6 12 −29.54 Tele facetUnit mm Surface data Surface number r d nd νd  1* 33.245 1.30 1.7291654.7  2* 144.445 1.95  3* 12.849 1.40 1.59240 68.3  4* −9.797 0.97 5(stop) ∞ 0.20  6* −13.239 0.80 1.80518 25.4  7* 60.932 0.20  8* 5.7881.20 1.64000 60.1  9* 4.534 1.35 10* 5.805 1.80 1.59240 68.3 11* 4.6591.28 12* 5.752 1.00 1.84666 23.8 13* 6.534 Image plane ∞ Aspherical data1st surface K = −8.19456e+001 A 4 = −5.31853e−004 A 6 = −7.42778e−0062nd surface K = −9.00000e+001 A 4 = 9.14133e−005 A 6 = 1.43749e−005 3rdsurface K = −1.08476e+001 A 4 = 1.16459e−003 A 6 = −1.83197e−005 4thsurface K = 9.72251e−001 A 4 = 1.35326e−004 A 6 = 7.81170e−006 6thsurface K = −6.39115e+001 A 4 = 2.15637e−003 A 6 = 1.05300e−005 7thsurface K = −9.00000e+001 A 4 = 4.80467e−003 A 6 = 7.24665e−005 8thsurface K = −1.02518e+001 A 4 = 6.60769e−003 A 6 = 1.61089e−004 9thsurface K = 1.25753e+000 A 4 = −2.95145e−005 A 6 = 3.76702e−004 10thsurface K = −1.25455e+000 A 4 = −1.16553e−003 A 6 = 2.81324e−005 11thsurface K = −4.99122e+000 A 4 = 1.63656e−003 A 6 = −1.60913e−004 12thsurface K = −5.81002e−001 A 4 = −3.88415e−003 A 6 = 1.65437e−004 13thsurface K = 1.22656e+000 A 4 = −4.86561e−003 A 6 = 1.16617e−004 Variousdata Focal length 15.00 F number 2.88 Half angle of field 14.48 Imageheight 3.88 Total lens length 18.00 BF 4.55 Entrance pupil position 5.25Exit pupil position −4.71 Front-side principal position −4.04 Rear-sideprincipal position −10.45 Single lens data Lens Start surface Focallength 1 1 58.93 2 3 9.60 3 6 −13.44 4 8 −52.19 5 10 −95.85 6 12 35.77

(NUMERICAL EXAMPLE 3) Wide facet Unit mm Surface data Surface number r dnd νd  1* −278.039 1.15 1.69680 55.5  2* 6.000 2.75  3* −13.838 1.551.59240 68.3  4* −4.335 0.50  5* 5.392 0.80 1.80518 25.4  6* 3.393 0.43 7(stop) ∞ 1.56  8* −20.462 1.20 1.64000 60.1  9* −3.385 0.59 10* 11.9951.65 1.59240 68.3 11* −11.271 1.37 12* −9.279 1.00 1.84666 23.8 13*9.946 Image plane ∞ Aspherical data 1st surface K = −1.51839e+001 A 4 =6.01752e−004 A 6 = 2.86999e−005 2nd surface K = 1.96510e+000 A 4 =−3.86322e−004 A 6 = −1.66133e−005 3rd surface K = 2.27610e+001 A 4 =−8.92074e−004 A 6 = −6.83728e−004 4th surface K = −7.29708e+000 A 4 =−6.23057e−003 A 6 = −1.69117e−004 5th surface K = −9.67598e−001 A 4 =−7.68250e−003 A 6 = −2.57460e−004 6th surface K = −4.96656e+000 A 4 =7.15623e−004 A 6 = 8.72707e−006 8th surface K = −6.04476e−001 A 4 =−1.54465e−003 A 6 = 2.57992e−004 9th surface K = −1.00603e+000 A 4 =−2.23851e−003 A 6 = −9.07492e−005 10th surface K = −3.55816e+001 A 4 =7.39878e−005 A 6 = −4.05799e−004 11th surface K = 3.15494e+000 A 4 =−5.45664e−003 A 6 = 4.27810e−005 12th surface K = −1.09737e+001 A 4 =−4.17651e−003 A 6 = 3.03530e−004 13th surface K = −1.89271e+001 A 4 =3.28962e−003 A 6 = 1.01426e−004 Various data Focal length 5.20 F number2.88 Half angle of field 36.69 Image height 3.88 Total lens length 18.00BF 3.45 Entrance pupil position 3.90 Exit pupil position −4.05Front-side principal position 5.49 Rear-side principal position −1.75Single lens data Lens Start surface Focal length 1 1 −8.41 2 3 10.05 3 5−13.83 4 8 6.17 5 10 10.07 6 12 −5.54 Wide-middle facet Unit mm Surfacedata Surface number r d nd νd  1* 246.153 1.15 1.69680 55.5  2* 6.0002.75  3* 27.183 1.55 1.59240 68.3  4* −4.038 0.50  5* 5.849 0.80 1.8051825.4  6* 3.626 0.43  7(stop) ∞ 1.56  8* −30.741 1.20 1.64000 60.1  9*−6.722 0.59 10* 5.066 1.65 1.59240 68.3 11* 6.280 1.37 12* 18.583 1.001.84666 23.8 13* 6.571 (variable) Image plane ∞ Aspherical data 1stsurface K = 9.00000e+001 A 4 = −8.39451e−004 A 6 = 2.35285e−005 2ndsurface K = −5.34082e+000 A 4 = 4.03329e−003 A 6 = −1.66191e−005 3rdsurface K = 6.33715e+001 A 4 = 2.67153e−003 A 6 = −1.61664e−004 4thsurface K = −5.22262e+000 A 4 = −1.37728e−003 A 6 = 2.77794e−005 5thsurface K = −2.62749e+000 A 4 = −9.55365e−003 A 6 = 2.40785e−004 6thsurface K = −5.84224e+000 A 4 = −6.94200e−003 A 6 = 1.86444e−004 8thsurface K = 9.00000e+001 A 4 = 8.35122e−003 A 6 = 1.58826e−004 9thsurface K = −1.03311e+001 A 4 = 3.42515e−003 A 6 = 6.46597e−004 10thsurface K = −3.10477e+000 A 4 = 3.57728e−003 A 6 = 1.57487e−004 11thsurface K = −3.74031e+000 A 4 = −8.18470e−004 A 6 = 4.37137e−004 12thsurface K = −9.00000e+001 A 4 = −7.97372e−003 A 6 = 3.60044e−004 13thsurface K = −1.19739e+001 A 4 = −3.83591e−003 A 6 = 4.12780e−004 Variousdata Focal length 7.50 F number 2.88 Half angle of field 27.32 Imageheight 3.88 Total lens length 18.00 BF 3.45 Entrance pupil position 4.17Exit pupil position −3.91 Front-side principal position 4.03 Rear-sideprincipal position −4.05 Single lens data Lens Start surface Focallength 1 1 −8.84 2 3 6.05 3 5 −14.11 4 8 13.19 5 10 29.38 6 12 −12.48Tele-middle facet Unit mm Surface data Surface number r d nd νd  1*42.658 1.15 1.69680 55.5  2* 8.092 2.75  3* 3.713 1.55 1.59240 68.3  4*−32.881 0.50  5* 5.257 0.80 1.80518 25.4  6* 3.116 0.43  7(stop) ∞ 1.56 8* −5.288 1.20 1.64000 60.1  9* −4.931 0.59 10* 5.092 1.65 1.59240 68.311* 5.827 1.37 12* 11.995 1.00 1.84666 23.8 13* 7.874 Image plane ∞Aspherical data 1st surface K = −2.66383e+001 A 4 = −2.18872e−003 A 6 =6.31429e−005 2nd surface K = 2.08397e+000 A 4 = −3.26063e−003 A 6 =2.84905e−005 3rd surface K = 1.10583e−001 A 4 = 2.75665e−004 A 6 =−1.47214e−005 4th surface K = −6.74747e+001 A 4 = 3.16266e−003 A 6 =−8.64586e−005 5th surface K = −1.66566e+000 A 4 = −3.71526e−003 A 6 =1.34066e−004 6th surface K = 5.41702e−001 A 4 = −9.62595e−003 A 6 =1.70734e−004 8th surface K = 3.16668e+000 A 4 = 4.62242e−003 A 6 =1.81580e−004 9th surface K = 1.69035e+000 A 4 = 5.27071e−003 A 6 =1.69765e−004 10th surface K = 1.136736+000 A 4 = 3.22950e−006 A 6 =2.93792e−005 11th surface K = 2.99335e+000 A 4 = −2.40678e−003 A 6 =7.59485e−005 12th surface K = −9.39873e+000 A 4 = −2.70967e−003 A 6 =5.48169e−005 13th surface K = −8.61644e+000 A 4 = −1.90799e−003 A 6 =9.68595e−005 Various data Focal length 10.50 F number 2.88 Half angle offield 20.26 Image height 3.88 Total lens length 18.00 BF 3.45 Entrancepupil position 5.41 Exit pupil position −4.58 Front-side principal pointposition 2.18 Rear-side principal point position −7.05 Single lens dataLens Start surface Focal length 1 1 14.53 2 3 5.72 3 5 −11.40 4 8 49.395 10 37.12 6 12 −30.46 Tele facet Unit mm Surface data Surface number rd nd νd  1* 8.009 1.15 1.69680 55.5  2* 7.508 2.75  3* 3.702 1.551.59240 68.3  4* 88.710 0.50  5* 7.031 0.80 1.80518 25.4  6* 3.311 0.43 7(stop) ∞ 1.56  8* −9.083 1.20 1.64000 60.1  9* 25.053 0.59 10* 7.5031.65 1.59240 68.3 11* 15.709 1.37 12* 5.989 1.00 1.84666 23.8 13* 7.775Image plane ∞ Aspherical data 1st surface K = 5.90804e−001 A 4 =−3.95356e−004 A 6 = −1.87359e−005 2nd surface K = 9.02179e−001 A 4 =−6.68247e−004 A 6 = −4.35238e−005 3rd surface K = 7.86019e−002 A 4 =1.00348e−004 A 6 = 5.36889e−006 4th surface K = 9.00000e+001 A 4 =2.36995e−003 A 6 = −5.00552e−005 5th surface K = −5.90637e+000 A 4 =−5.74098e−004 A 6 = 1.24577e−004 6th surface K = 7.11639e−001 A 4 =−6.13172e−003 A 6 = 2.01076e−004 8th surface K = 9.12926e+000 A 4 =5.29083e−003 A 6 = −8.33091e−004 9th surface K = 9.00002e+001 A 4 =6.28003e−003 A 6 = −7.33225e−004 10th surface K = 1.72371e+000 A 4 =−2.97948e−004 A 6 = −2.54947e−006 11th surface K = −6.66245e+001 A 4 =−1.60347e−003 A 6 = 1.06542e−004 12th surface K = −3.71090e+000 A 4 =−1.38172e−003 A 6 = 1.02692e−004 13th surface K = 1.93714e+000 A 4 =−3.41454e−003 A 6 = 1.05240e−004 Various data Focal length 15.00 Fnumber 2.88 Half angle of field 14.48 Image height 3.88 Total lenslength 18.00 BF 3.45 Entrance pupil position 8.15 Exit pupil position−6.16 Front-side principal point position −0.26 Rear-side principalpoint position −11.55 Single lens data Lens Start surface Focal length 11 −2975.24 2 3 6.48 3 5 −8.60 4 8 −10.28 5 10 22.56 6 12 24.50

(NUMERICAL EXAMPLE 4) Wide facet Unit mm Surface data Surface number r dnd νd  1* 9.963 1.30 1.62041 60.3  2* 2.063 3.16  3* 5.403 1.40 1.5924068.3  4* −11.150 0.60  5* −43.751 0.80 1.80518 25.4  6* 15.608 0.10 7(stop) ∞ 0.10  8* 4.764 1.20 1.64000 60.1  9* −66.999 2.94 10* 14.4041.80 1.59240 68.3 11* −9.500 0.50 12* −17.138 1.00 1.84666 23.8 13*11.853 Image plane ∞ Aspherical data 1st surface K = −2.47869e+001 A 4 =−2.02166e−003 A 6 = 5.43003e−005 2nd surface K = −1.79551e+000 A 4 =1.25374e−002 A 6 = −4.89811e−005 3rd surface K = 2.24981e+000 A 4 =2.67772e−003 A 6 = 1.71832e−004 4th surface K = −2.15785e+001 A 4 =1.38585e−003 A 6 = −4.29296e−005 5th surface K = −7.77189e+000 A 4 =2.90232e−003 A 6 = −1.23226e−003 6th surface K = 5.52064e+001 A 4 =2.30902e−003 A 6 = −9.38603e−004 8th surface K = 6.43691e−001 A 4 =1.22013e−003 A 6 = 3.62473e−004 9th surface K = −6.95418e+001 A 4 =3.79577e−003 A 6 = 8.00925e−004 10th surface K = −9.00000e+001 A 4 =5.32715e−003 A 6 = 4.14940e−004 11th surface K = 1.36769e+001 A 4 =−2.97992e−003 A 6 = 1.43850e−003 12th surface K = −9.00000e+001 A 4 =−2.16468e−002 A 6 = 4.36176e−004 13th surface K = 1.40560e+001 A 4 =−1.25552e−002 A 6 = 5.78256e−004 Various data Focal length 5.20 F number2.88 Half angle of field 36.69 Image height 3.88 Total lens length 17.77BF 2.87 Entrance pupil position 3.58 Exit pupil position −4.59Front-side principal point position 5.15 Rear-side principal pointposition −2.33 Single lens data Lens Start surface Focal length 1 1−4.47 2 3 6.34 3 5 −14.20 4 8 6.99 5 10 9.94 6 12 −8.15 Tele facet Unitmm Surface data Surface number r d nd νd  1* 32.268 1.30 1.62041 60.3 2* −51.647 3.16  3* 5.700 1.40 1.59240 68.3  4* −12.800 0.60  5* −9.9990.80 1.80518 25.4  6* 191.283 0.10  7(stop) ∞ 0.10  8* 5.214 1.201.64000 60.1  9* 2.487 2.94 10* 18.649 1.80 1.59240 68.3 11* 26.555 0.5012* 8.399 1.00 1.84666 23.8 13* 11.838 Image plane ∞ Aspherical data 1stsurface K = −1.92634e+001 A 4 = −2.82433e−004 A 6 = 3.81416e−006 2ndsurface K = 9.00000e+001 A 4 = 3.23423e−004 A 6 = 2.68125e−006 3rdsurface K = −8.60800e−001 A 4 = 2.63313e−003 A 6 = 4.15438e−005 4thsurface K = −2.86471e+001 A 4 = 8.10119e−004 A 6 = 2.03306e−006 5thsurface K = 9.11794e+000 A 4 = 5.04006e−003 A 6 = 2.54023e−004 6thsurface K = 7.38599e+001 A 4 = 2.81749e−003 A 6 = 5.63571e−004 8thsurface K = −8.57667e−001 A 4 = −3.65406e−003 A 6 = −4.84007e−004 9thsurface K = −2.26017e−001 A 4 = −3.68837e−003 A 6 = −1.37027e−003 10thsurface K = 1.65894e+001 A 4 = 2.55538e−003 A 6 = 1.45887e−005 11thsurface K = 9.21247e+000 A 4 = 2.90663e−004 A 6 = −7.09973e−006 12thsurface K = −7.20764e+000 A 4 = −1.10889e−003 A 6 = −5.90829e−005 13thsurface K = 8.94495e+000 A 4 = −3.28402e−003 A 6 = −4.17715e−005 Focallength 15.00 F number 2.88 Half angle of field 14.48 Image height 3.88Total lens length 17.77 BF 2.87 Entrance pupil position 8.12 Exit pupilposition −6.28 Front-side principal point position −1.49 Rear-sideprincipal point position −12.13 Single lens data Lens Start surfaceFocal length 1 1 32.20 2 3 6.85 3 5 −11.78 4 8 −8.97 5 10 97.49 6 1230.14

TABLE 1 EMBODIMENT FACET TYPE 1 2 3 4 A 1.00 0.94 1.11 1.04 B 1.00 0.901.01 1.00 C 1.00 1.00 0.99 D 1.00 1.00 1.00

This application claims the benefit of Japanese Patent Application No.2014-227662, filed on Nov. 10, 2014, which is hereby incorporated byreference herein in its entirety.

What is claimed is:
 1. A control apparatus comprising: a focus detectorconfigured to perform focus detection based on an image signal obtainedvia a first optical system, the first optical system having a shallowestdepth of field in a plurality of optical systems having focal lengthsdifferent from each other; and a controller configured to perform focuscontrol of the plurality of optical systems based on an output signalfrom the focus detector.
 2. The control apparatus according to claim 1,further comprising a calculator configured to calculate a movementposition of a focus lens of a second optical system in the plurality ofoptical systems, wherein: the controller is configured to perform thefocus control by moving a focus lens of the first optical system basedon the output signal from the focus detector, and the calculator isconfigured to calculate the movement position of the focus lens of thesecond optical system based on a position of the focus lens of the firstoptical system.
 3. The control apparatus according to claim 1, whereinthe controller is configured to perform the focus control by integrallymoving a plurality of focus lenses of the plurality of optical systemsby an identical moving amount based on the output signal from the focusdetector.
 4. The control apparatus according to claim 1, furthercomprising: an acquirer configured to acquire image capturing conditioninformation; and a determiner configured to determine the first opticalsystem based on the image capturing condition information.
 5. Thecontrol apparatus according to claim 4, wherein: the acquirer isconfigured to acquire, as the image capturing condition information,information relating to the plurality of optical systems, focal lengthsof the optical systems, and F numbers of the optical systems, and thedeterminer is configured to determine the first optical systemsatisfying a conditional expression below:${\frac{f_{i}^{2}}{{Fno}_{i}} \leq \frac{f_{1}^{2}}{{Fno}_{1}}},$ wheref₁ is a focal length of the first optical system, Fno₁ is an F number ofthe first optical system, f_(i) is a focal length of one of the opticalsystems, and Fno_(i) is an F number of the one of the optical systems.6. The control apparatus according to claim 1, wherein the focusdetector is configured to perform the focus detection by a contrastdetection method.
 7. The control apparatus according to claim 1, whereinthe focus detector is configured to perform the focus detection by aphase-difference detection method.
 8. The control apparatus according toclaim 1, wherein the focus detector includes: a first focus detectorconfigured to perform focus detection by a phase-difference detectionmethod, and a second focus detector configured to perform focusdetection by a contrast detection method, and wherein the controller isconfigured to: perform first focus control based on a first outputsignal from the first focus detector, and perform second focus controlbased on a second output signal from the second focus detector after thefirst focus control.
 9. The control apparatus according to claim 4,further comprising: a region determiner configured to determine a regionin which the focus detection is to be performed; and an inclusiondeterminer configured to determine whether the region determined by theregion determiner is included in an image pickup region for each of theplurality of optical systems, wherein the determiner is configured todetermine the first optical system based on a determination result ofthe inclusion determiner.
 10. An image pickup apparatus comprising: animage pickup element configured to photoelectrically convert an opticalimage formed via a plurality of optical systems having focal lengthsdifferent from each other; a focus detector configured to perform focusdetection based on an image signal obtained via a first optical system,the first optical system having a shallowest depth of field in theplurality of optical systems; and a controller configured to performfocus control of the plurality of optical systems based on an outputsignal from the focus detector.
 11. The image pickup apparatus accordingto claim 10, wherein the image pickup element includes a plurality ofimage pickup regions corresponding to the respective optical systems.12. An image pickup system comprising: a plurality of optical systemshaving focal lengths different from each other; an image pickup elementconfigured to photoelectrically convert an optical image formed via theplurality of optical systems; a focus detector configured to performfocus detection based on an image signal obtained via a first opticalsystem, the first optical system having a shallowest depth of field inthe plurality of optical systems; and a controller configured to performfocus control of the plurality of optical systems based on an outputsignal from the focus detector.
 13. The image pickup system according toclaim 12, wherein the plurality of optical systems include at least twooptical systems having an identical focal length.
 14. The image pickupsystem according to claim 12, further comprising a holder configured tointegrally move a plurality of focus lenses of the optical systems by anidentical moving amount during the focus control of the optical systems.15. A lens apparatus comprising: a plurality of optical systems havingfocal lengths different from each other; and a controller configured toperform focus control of the plurality of optical systems based on animage signal obtained via a first optical system, the first opticalsystem having a shallowest depth of field in the plurality of opticalsystems.
 16. A control method comprising the steps of: performing focusdetection based on an image signal obtained via a first optical system,the first optical system having a shallowest depth of field in aplurality of optical systems having focal lengths different from eachother; and performing focus control of the plurality of optical systemsbased on a result of the focus detection.
 17. A non-transitorycomputer-readable storage medium storing a program which causes acomputer to execute a process comprising: performing focus detectionbased on an image signal obtained via a first optical system, the firstoptical system having a shallowest depth of field in a plurality ofoptical systems having focal lengths different from each other; andperforming focus control of the plurality of optical systems based on aresult of the focus detection.